Approximation / Simplification

Approximation is one of the most important topics among Bank and Insurance Exams like RRB Scale 1 Pre, SBI Clek Pre, IBPS PO Pre, and NIACL Etc. If you are good at maths basics then you can easily gain 4 to 5 marks in just 3 to 5 minutes.
 

Here we will discuss some important questions on approximation.

Directions: What approximate value should come in place of Question mark (?) in the following question?

Question1:  (2356.237 × 4.9) – 1357.895 + 1124.237 – 425.231 + (35 × 1.23) = ?

A. 19052

B. 12952

C. 11156

D. 8992

E. 13852

Solution: 

(2356.237 × 4.9) – 1357.895 + 1124.237 – 425.231 + (35 × 1.23) = ?
? = (2356 × 5) – 1358 + 1124 – 425 + (35 × 1)
? = 11780 – 1358 + 1124 – 425 + 35
? = 11780 – 624 = 11156
Hence, option C is correct.

Question 2: 470.005 × 99.92 + 337.89 + 472.05 – 137.88 × 0.98 = ?
A. 58447

B. 47672

C. 68947

D. 40132

E. 35000

Solution:  470.005 × 99.92 + 337.89 + 472.05 – 137.88 × 0.98 = ?
? ≈ 470 × 100 + 338 + 472 – 138 × 1
? ≈ 47000 + 810 – 138
? ≈ 47672
Hence, option B is correct.

Question 3 :   2222.1 × 11 + 3333.1 × 11.01 + 4444 × 11 + 5555 × 11 – 6666.1 × 11 = ?
A. 10864

B. 86884

C. 97768

D. 77768

E. 88768

Solution: 
2222.1 × 11 + 3333.1 × 11.01 + 4444 × 11 + 5555 × 11 – 6666.1 × 11 = ?
? ≈ 2222 × 11 + 3333 × 11 + 4444 × 11 + 5555 × 11 – 6666 × 11
= 11[2222 + 3333 + 4444 + 5555 – 6666]
= 11[2222 + 3333 + 4444 + 5555 – 6666]
= 11 × 8888 = 97768
Hence, option C is correct.

Question 4:  ?% of (5284.89 ÷ 7.08) = 986.01 – 533.06
A. 42

B. 39

C. 74

D. 65

E. 60

Solution: 

?% of (5284.89 ÷ 7.08) = 986.01 – 533.06
≈ ?% of (5285 ÷ 7) = 986 - 533
⇒ ? × (755) = 453 × 100
⇒ ? =453 × 100/755
= 60
Hence, option E is correct.

Question 5:

√8837 × 20 × 4.25 + √5040 × 10 × 8.75 – √4489 × 5 × 1.25 = ?
A. 13575

B. 17255

C. 22485

D. 21850

E. 3785

Solution:

√8837 × 20 × 4.25 + √5040 × 10 × 8.75 – √4489 × 5 × 1.25 = ?

? ≈ √ × 20 × 4 + √ × 10 × 9 – √ × 5 × 1

= 94 × 80 + 71 × 90 – 67 × 5

= 7520 + 6390 – 335

 = 13575

Question 6: 

0.003 × 0.9 × 0.005 × 0.2 + 0.008 × 0.5 + 25.85 – 23.05 = ?
A. 17

B. 11

C. 3

D. 5

E. None of these

Solution: 

0.003 × 0.9 × 0.005 × 0.2 + 0.008 × 0.5 + 25.85 – 23.05 = ?
? = 0.0027 × 0.0001 + 0.004 + 25.85 – 23.05
= 0.0000027 + 0.004 + 2.8
= 2.8040027 ≈ 3
Hence, option C is correct.

Question 7: (?)² + (125)² = (250.13)² – (95.12)² – 5680
A. 160

B. 165

C. 170

D. 179

E. 190

Solution:

(?)² + (125)² = (250.13)² – (95.12)² – 5680

(?)² + 15625 = ≈ (250)² – (95)² – 5680

(?)² + 15625 = 62500 – 9025 – 5680

(?)² + 15625 = 47795

(?)² = 47795 – 15625 = 32170

? = 179.35

? ≈ 179 Hence, option D is correct.