4
Q:

# Two boxes contain 4 and 16 balls respectively. Two balls in the first box and four in the second, are black. If a box is chosen randomly and two balls are drawn at random from it, what is theprobability that at least one ball is black if the ball is not replaced?

 A) 11/20 B) 43/120 C) 77/120 D) 9/20

Explanation:

At least one black can be chosen in two ways from each box:
Now, probability of choosing at least one black ball from first box

= 1/2 × [ (2C1× 2C1)/4C2 + 2C2/ 4C2 ]= 5/12

Probability of choosing at least one black ball from 2nd box
= 1/2 × [(4C1×12C1)/16C2 + 4C2/ 16C2] = 9/40

Final probability

= 5/12 + 9/40 = (50 + 27)/120 = 77/120

Q:

Three of the following four word-pairs are alike in a certain way and one is different. Pick the odd one out.

 A) Chisel : Sculptor B) Anvil : Blacksmith C) Paper : Book D) Scalpel : Surgeon

Answer & Explanation Answer: C) Paper : Book

Explanation:

0 50
Q:

A certain sum is divided among A, B, C and D such that the ratio of the shares is A : B : C : D = 4 : 12 : 30 : 45. If the difference between the shares of A and D is ₹5,535, then the total sum (in ₹) is:

 A) 12785 B) 13550 C) 12285 D) 11000

Explanation:

0 43
Q:

Select the correct combination of mathematical signs that can sequentially replace the * signs and balance the equation.
512*32*9*100*6*25*2

 A) ÷, ×, +, =, −, × B) ÷, ×, +, −, =, × C) ÷, ×, −, +, =, × D) +, ×, ÷, =, −, ×

Answer & Explanation Answer: C) ÷, ×, −, +, =, ×

Explanation:

0 38
Q:

Select the option in which the numbers are related in the same way as are the numbers of the following set.

173 : 125 : 85

 A) 365 : 293 : 229 B) 285 : 221 : 135 C) 259 : 199 : 147 D) 293 : 228 : 171

Answer & Explanation Answer: A) 365 : 293 : 229

Explanation:

0 168
Q:

If sqrt x + frac{1}{sqrt x} = 2sqrt2, then x^2 + frac{1}{x^2} is equal to:

 A) 36 B) 34 C) 32 D) 64

Explanation:

2 249
Q:

If a + b + c = 8 and ab + bc + ca = 20, then a^3 + b^3 + c^3 - 3abc is equal to:

 A) 30 B) 24 C) 32 D) 36

Explanation:

1 1696
Q:

The usual average speed of a car on a particular stretch of road is 75 km/hr. On a particular day, the average speed was 12% less than the usual, as a result of which the time taken was I S minutes more.

How long is the stretch of road, in kilometres?

 A) 155 B) 176 C) 165 D) 150

Explanation:

1 353
Q:

In an examination in which the full marks were 500, A scored 25% more marks than B, B scored 60% more marks than C and C scored 20% less marks than D. IfA scored 80% marks, then the percentage of marks obtained by is:

 A) 65% B) 60% C) 50% D) 54%