5
Q:

# There are 6561 balls are there out of them 1 is heavy. Find the minimum number of times the balls have to be weighted for finding out the heavy ball ?

 A) 2414 B) 204 C) 87 D) 8

Explanation:

Suppose there are 9 balls

Let us give name to each ball B1 B2 B3 B4 B5 B6 B7 B8 B9

Now we will divide all the balls into 3 groups.

Group1 - B1 B2 B3

Group2 - B4 B5 B6

Group3 - B7 B8 B9

Step1 - Now weigh any two groups. Let's assume we choose Group1 on left side of the scale and Group2 on the right side.

So now when we weigh these two groups we can get 3 outcomes.

Weighing scale tilts on left - Group1 has a heavy ball.
Weighing scale tilts on right - Group2 has a heavy ball.
Weighing scale remains balanced - Group3 has a heavy ball.
Lets assume we got the outcome as 3. i.e Group 3 has a heavy ball.

Step2 - Now weigh any two balls from Group3. Lets assume we keep B7 on left side of the scale and B8 on right side.

So now when we weigh these two balls we can get 3 outcomes.

Weighing scale tilts on left - B7 is the heavy ball.
Weighing scale tilts on right - B8 is the heavy ball.
Weighing scale remains balanced - B9 is the heavy ball.
The conclusion we get from this Problem is that each time weigh. We element 2/3 of the balls.

As we came to conclusion that Group3 has the heavy ball from Step1, we remove 6 balls from the equation i.e (2/3) of 9.

Simillarly we do the ame thing for the Step2.

Now going with this conclusion. We have 6561 balls.

Step - 1

Divided into 3 groups

Group1 - 2187Balls

Group2 - 2187Balls

Group3 - 2187Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 2

Divided into 3 groups

Group1 - 729Balls

Group2 - 729Balls

Group3 - 729Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 3

Divided into 3 groups

Group1 - 243Balls

Group2 - 243Balls

Group3 - 243Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 4

Divided into 3 groups

Group1 - 81Balls

Group2 - 81Balls

Group3 - 81Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 5

Divided into 3 groups

Group1 - 27Balls

Group2 - 27Balls

Group3 - 27Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 6

Divided into 3 groups

Group1 - 9Balls

Group2 - 9Balls

Group3 - 9Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 7

Divided into 3 groups

Group1 - 3Balls

Group2 - 3Balls

Group3 - 3Balls

Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.

Step - 8

So now when we weigh 2 balls out of 3 we can get 3 outcomes.

Weighing scale tilts on left - left side placed is the heavy ball.
Weighing scale tilts on right - right side placed is the heavy ball.
Weighing scale remains balanced - remaining ball is the heavy ball.
So the general answer to this question is, it is always multiple of 3 steps.

For 9 balls  ${3}^{2}$= 9. therefore 2 steps

For 6561 balls ${3}^{8}$ = 6561 therefore 8 steps

Q:

"Compounding frequency" refers to

 A) What type of interest your account earns B) How often your interest is calculated and added back into your account C) What interest rate you can expect from your account D) How easily you can add money into your account

Explanation:

Compounding frequency :

The time periods when interest will be calculated on top of the original loan amount (or) The number of compounding periods in one year.

The greater the compounding frequency, the more often your interest is calculated and added back into your account.

0 113
Q:

How many inches is 5' 4"?

 A) 66 B) 64 C) 62 D) 60

Explanation:

We know 1 feet = 12 inches.

According to the question,

5' 4''  =  5 feet 4 inches = 12 x 5 + 4 = 64 inches.

Hence,  5' 4''  =  5 feet 4 inches = 64 inches.

0 85
Q:

Multiplicative inverse of 0

 A) 0 B) 1 C) infinity D) None of the above

Explanation:

In the real numbers, zero does not have a reciprocal because no real number multiplied by 0 produces 1 (the product of any number with zero is zero).

Hence, 0 doesn't have any multiplicative inverse.

0 126
Q:

6 divided by 2(1 + 2) =

 A) 1 B) 0 C) 9 D) Can't be determined

Explanation:

The given expression can be simplified as

$÷$ 2 (1 + 2)

The expression can be simplified further by the order of operations, using BODMAS rule.

First evaluate Parentheses/Brackets, then evaluate Exponents/Orders, then evaluate Multiplication-Division, and finally evaluate Addition-Subtraction.

Now, the expression becomes $÷$ 2 (3)

According to the order of operations, division and multiplication have the same precedence, so the correct order is to evaluate from left to right. First take 6 and divide it by 2, and then multiply by 3.

6 ÷ 2 × 3

= 3 × 3

= 9

But not  6÷2×3 = 6 ÷ 6 = 1

Hence, 6 ÷ 2 (1 + 2) = 9.

1 141
Q:

Multiplicative inverse of 7?

 A) 1 B) -1/7 C) 0 D) 1/7

Explanation:

Multiplicative inverse is nothing but a reciprocal of a number.

It is defined as one of a pair of numbers that when multiplied with another number equals the number 1.

Multiplicative inverse or reciprocal of 7 is

7 x n = 1

=> n = 1/7.

Hence, Multiplicative inverse or reciprocal of 7 is  1/7.

2 119
Q:

What is the product of a number and its reciprocal?

 A) 0 B) 1 C) -ve of the number D) the number itself

Explanation:

The product of a number and its reciprocal is always equals to 1.

For Example : Let the number be 4.

Now, its reciprocal is 1/4

Hence, required product = 4 x 1/4 = 1.

Now, take the number as -15.

Then its reciprocal is -1/15

Required product = -15 x -1/15 = 1.

Hence, the product of a number and its reciprocal is 1.

0 149
Q:

A plane is an undefined term because it

 A) is a flat surface that extends indefinitely in all directions B) is where other geometric shapes can be constructed C) is described generally, not using a formal definition D) can be named using three noncollinear points

Answer & Explanation Answer: C) is described generally, not using a formal definition

Explanation:

In geometry, we can define plane as a flat surface with no thickness.

The surface extends with no ends.

A plane does not have any edges even if we draw it on paper with edges, it does't mean it has edges.

Hence, A plane is an undefined term because it is described generally, not using a formal definition.

0 204
Q:

Absolute value of 9?

 A) 0 B) 9 C) 8 D) -9

Explanation:

Absolute value of a number :

It means that the distance of a number from 0 on a number line.

Here absolute value of 9 is that on a number line 9 is 9 units away from 0. Hence its absolute value is 9. Similarly, absolute value of -9 means -9 is also 9 units away from the 0 on number line. Hence, absolute value of -9 is also 9.

Hence, the absolute value of 9 is 9.