Simplification Questions

FACTS  AND  FORMULAE  FOR  SIMPLIFICATION  QUESTIONS

 

 

1. BODMAS Rule: This rule depicts the correct sequence in which the operations are to be executed,so as to find out the value of a given expression. Here, 'B' stands for bracket , 'O' for of , 'D' for division and 'M' for multiplication, 'A' for addition and 'S' for subtraction.

Thus, in simplifying an expression, first of all the brackets must be removed, strictly in the order(), {} and [].

After removing the brackets, we must use the following operations strictly in the order:

(1) of    (2)division   (3) multiplication   (4)addition   (5)subtraction.

 Modulus of a real number : Modulus of a real number a is defined as |a| = aif a>0-aif a<0

 

2. Virnaculum (or bar) : When an expression contains Virnaculum, before applying the ‘BODMAS’ rule, we simplify the expression under the Virnaculum.

Q:

If a + b + c = 13, a2+b2+c2=69 then find the ab + bc + ca :

A) 10 B) 30
C) 50 D) 70
 
Answer & Explanation Answer: C) 50

Explanation:

a+b+c2=a2+b2+c2+2ab+bc+ca

2ab+bc+ca=a+b+c2-a2+b2+c2=169-69=100=ab+bc+ca=50

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52 30304
Q:

In a regular week, there are 5 working days and for each day, the working hours are 8. A man gets Rs. 2.40 per hour for regular work and Rs. 3.20 per hours for overtime. If he earns Rs. 432 in 4 weeks, then how many hours does he work for ?

A) 160 B) 175
C) 180 D) 195
 
Answer & Explanation Answer: B) 175

Explanation:

Suppose the man works overtime for x hours.

Now, working hours in 4 weeks = (5 x 8 x 4) = 160.

Therefore,  160 * 2.40 + x * 3.20 = 432

 => 3.20x = 432 - 384 = 48

 => x = 15.

 Hence, total hours of work = (160 + 15) = 175.

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34 30148
Q:

A tank is 2/5 full. If 16 litres of water is added to the tank, it becomes 6/7 full. The capacity of the tank is:

A) 28 litres B) 32 litres
C) 35 litres D) 42 litres
 
Answer & Explanation Answer: C) 35 litres

Explanation:

Let the capacity of the tank be x litres.

 

Then, (6x/7 - 2x/5) = 16 <=> 30x - 14x = 16*35 <=> x = 35

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34 22714
Q:

The total of 324 of 20 paise and 25 paise make a sum of Rs. 71. The no of 20 paise coins is :

A) 50 B) 100
C) 150 D) 200
 
Answer & Explanation Answer: D) 200

Explanation:

Let the number  of 20 paise coins be x. Then the no of 25 paise coins = (324 - x).

0.20 * (x) + 0.25 (324 - x) = 71 => x = 200..

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19 16650
Q:

The difference of 18 and its reciprocal is equal to :

A) 1/8 B) 4/3
C) 15/16 D) 105/304
 
Answer & Explanation Answer: D) 105/304

Explanation:

Required difference = 19/16 - 16/19  =  105/304..

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42 15477
Q:

217 x 217 + 183 x 183 = ?

A) 84521 B) 87487
C) 80578 D) 78458
 
Answer & Explanation Answer: C) 80578

Explanation:

2172+1832

 

= 200+172+200-172

 

It is in the form of a+b2+a-b2=2a2+b2

 

= 2(40000 + 289) = 80578.

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20 14786
Q:

In a group of buffaloes and ducks, the number of legs are 24 more than twice the number of heads. What is the number of buffaloes in the group ?

A) 6 B) 10
C) 8 D) 12
 
Answer & Explanation Answer: D) 12

Explanation:

Let the number of buffaoes be x and number of ducks be y.

Then 4x + 2y = 2(x + y) + 24  

=> 2x = 24

=> x = 12.

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18 14544
Q:

The highest score in an inning was  3/11 of the total and the next highest was 3/11 of the reminder . If the score  differ by 9, the total score was :

A) 110 B) 121
C) 132 D) 143
 
Answer & Explanation Answer: B) 121

Explanation:

Let the score be x. Then the highest score = 3x/11.

Reminder = (x - 3x/11) = 8x/11 .Next the highest score = 3/11 of 8x/11 = 24x/121.

3x/11 - 24x/11 = 9 <=> 33x - 24x = 9*121 <=> x= 121..

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17 12969