Category: Mathematics

A. 45
B. 46
C. 47
D. 48

Solution:
Total age of students = 30×15 = 450
Including teacher = 31×16 = 496
Teacher’s age = 496 – 450 = 46
Answer: B

A. 36
B. 40
C. 42
D. 56

Solution:
Pattern: n² + n → 1²+1=2, 2²+2=6, 3²+3=12 …
Next = 6²+6 = 42
Answer: C

A. 100 km
B. 110 km
C. 115 km
D. 120 km

Solution:
Time = 2.5 h → Distance = Speed × Time = 48 × 2.5 = 120
Answer: D

A. 170
B. 190
C. 210
D. 310

Solution:
LCM(12,18,30)=180
Required number = 180k + 10
Smallest = 180 + 10 = 190
Answer: B

A. 35
B. 37.5
C. 40
D. 42.5

Solution:
(15/100) × 250 = 37.5
Answer: B

A. 15%
B. 16%
C. 18%
D. 20%

Solution:
CP of 12 pens = SP of 10 pens
So, CP:SP = 10:12 = 5:6
Profit = 1 on CP=5 → %Gain = (1/5)×100 = 20%
Answer: D

A. 78
B. 136
C. 156
D. 168

Solution:
Sum(1+2+…+12)=78 strikes in 12 hours
In 24 hours = 78 × 2 = 156
Answer: C

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

A. 1225
B. 1250
C. 1275
D. 1300

Solution:
Formula = n(n+1)/2 = 50 × 51 / 2 = 1275
Answer: C

A. 90%
B. 109%
C. 190%
D. 1009%

Solution:
1.09 × 100 = 109%
Answer: B