SBI PO : Approximation based aptitude questions

APPROXIMATION
Directions: What approximate value will come in place of question mark (?) in
the following questions (You are not expected to calculate the exact value).
1. 9228.789 – 5021.832 + 1496.989 = ?
a) 6500 b) 6000 c) 6300 d) 5700 e) 5100
ANSWER: d
Explanation:
Having a glance at the given options one can find out that the two nearest values
have a difference of 300. So round off the numbers to the nearest ten’s values.
9228.789 9230; 5021.832 5020 and 1496.989 1500
Now the equation will become
9230 – 5020 + 1500 = ?
? = 5710
But the nearest value is 5700.
[Note: Even rounding of the numbers to nearest hundred places gives the same
answer]

2. 1002 ÷ 49 × 99 – 1299 = ?
a) 700 b) 600 c) 900 d) 250 e) 400
ANSWER: a
Explanation:
can be rounded off to the nearest ten’s places.
1002 1000; 49 50; 99 100 and 1299 1300
Now the equation will become
1000 ÷ 50 × 100 – 1300 = ?
20 × 100 – 1300 = ?
2000 – 1300 = ?
? = 700
3. 29.8% of 260 + 60.01% of 510 – 103.57 = ?
a) 450 b) 320 c) 210 d) 280 e) 350
ANSWER: d
Explanation:
The difference between two nearest values is 70 (210 and 280). So round off the
numbers to the nearest integers.
29.8% of 260 30% of 260; 60.01% of 510 60% of 510 and 103.57
104
Now the equation will become
30% of 260 + 60% of 510 – 104 = ?
30/100×260+60/100×510-104=?
78+306-104=?
? = 384 – 104 = 280
4. (21.98)2 – (25.02)2 + (13.03)2 = ?
a) 25 b) 120 c) 10 d) 65 e) 140
ANSWER: a
Explanation:
(21.98)2=222
(25.02)2=(25)2
and (13.03)2=(13)2
The equation will becomes
222 – 252 + 132 = ?
484 – 625 + 169 = ?
653 – 625 = ?
? = 28 so the nearest value is 25
5. √ 2498X √ 625 (modules) √ 99=?
a) 110 b) 90 c) 200 d) 160 e) 125
ANSWER: e