A. 15
B. 20
C. 25
D. 30
Solution:
If money doubles in 10 years → 100% SI in 10 years → Rate = 10%
To become 3 times → 200% SI needed → 200 ÷ 10 = 20 years
Answer: B
Tag: css math preparation
The sum of first 50 natural numbers is:
A. 1225
B. 1250
C. 1275
D. 1300
Solution:
Formula = n(n+1)/2 = 50 × 51 / 2 = 1275
Answer: C
Express 1.09 in percentage.
A. 90%
B. 109%
C. 190%
D. 1009%
Solution:
1.09 × 100 = 109%
Answer: B
25 men can consume 250 kg of wheat in 20 days. 20 men can consume how much wheat in 25 days?
A. 200
B. 250
C. 300
D. 350
Solution:
Work ∝ Men × Days
Total consumption = 250 kg
1 man-day consumption = 250 ÷ (25 × 20) = 0.5 kg
For 20 × 25 = 500 man-days → 500 × 0.5 = 250 kg
Answer: B
Find the missing number in the series: 1, 6, 13, 22, 33, ?
A. 44
B. 45
C. 46
D. 47
Solution:
Pattern: +5, +7, +9, +11 …
Next = 33 + 13 = 46
Answer: C
If 12 men can complete a work in 18 days, in how many days will 9 men complete the same work?
A. 20
B. 22
C. 24
D. 30
Solution:
Work ∝ Men × Days
12 × 18 = 9 × x
x = (12 × 18) / 9 = 24
Answer: C
A train 150 m long is running at a speed of 54 km/h. How long will it take to pass a man standing on a platform?
A. 8 sec
B. 10 sec
C. 12 sec
D. 15 sec
Solution:
Speed = 54 × 1000 / 3600 = 15 m/s
Time = Distance ÷ Speed = 150 ÷ 15 = 10 sec
Answer: B
The average of first five multiples of 3 is:
A. 9
B. 10
C. 11
D. 12
Solution:
Multiples: 3, 6, 9, 12, 15
Sum = 45 → Average = 45 ÷ 5 = 9
Answer: A
A number is increased by 20% and then decreased by 20%. The net change is:
A. 0%
B. 4% increase
C. 4% decrease
D. 2% decrease
Solution:
Effect = (20 – 20 – (20×20)/100) = –4%
Answer: C