The average age of three boys is 15 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?

Byadmin July 8, 2019August 4, 2021

The average age of three boys is 15 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?

A. 15
B. 9
C. 18
D. 21
3x + 5x + 7x = 45
x =3
3x = 9

Compound Interest | Mathematics Mcqs

The difference between simple interest and C.I. at the same rate for Rs.5000 for 2 years in Rs.72. The rate of interest is?

The difference between simple interest and C.I. at the same rate for Rs.5000 for 2 years in Rs.72. The rate of interest is?

A. 10%
B. 12%
C. 6%
D. 8%
Explanation:
5000 = 72(100/R)2
5 R2 = 720 => R = 12

Read More The difference between simple interest and C.I. at the same rate for Rs.5000 for 2 years in Rs.72. The rate of interest is?
Mathematics Mcqs | Time & Distance Mcqs

Two trains 120 miles apart travel towards each other. The 1st train travels at 70 mph while the 2nd at 50 mph. A bird starts flying from the location of the faster train towards the other train at 85 mph and when it reaches the slower train it turns back and flies in the other direction at the same speed. When it reaches the faster train it again turns around and repeats the same procedure again and again. When the train collide, how far will the bird have flown?

Two trains 120 miles apart travel towards each other. The 1st train travels at 70 mph while the 2nd at 50 mph. A bird starts flying from the location of the faster train towards the other train at 85 mph and when it reaches the slower train it turns back and flies in the other direction at the same speed. When it reaches the faster train it again turns around and repeats the same procedure again and again. When the train collide, how far will the bird have flown?

A. 85 miles
B. 70 miles
C. 50 miles
D. 120 miles

Read More Two trains 120 miles apart travel towards each other. The 1st train travels at 70 mph while the 2nd at 50 mph. A bird starts flying from the location of the faster train towards the other train at 85 mph and when it reaches the slower train it turns back and flies in the other direction at the same speed. When it reaches the faster train it again turns around and repeats the same procedure again and again. When the train collide, how far will the bird have flown?
Mathematics Mcqs | Simplification and Approximation

(815 / ?) / 100 * 28 * 3 – (815 * 14 * 6)/100 = 1680

(815 / ?) / 100 * 28 * 3 – (815 * 14 * 6)/100 = 1680

A. 2000
B. 3000
C. 4000
D. 6000
Explanation:
Let 815 + ? be k
=> 84k/100 – (815 * 84)/100 = 1680
=>84(k/100 – 815/100) = 1680
=> (k – 815)/100 = 20 => k = 2815
k = 815 + ? = 2815 => ? = 2000

Read More (815 / ?) / 100 * 28 * 3 – (815 * 14 * 6)/100 = 1680
Mathematics Mcqs | Simplification and Approximation

(0.9 * 0.9 – 0.8 * 0.8)/1.7 = _________?

(0.9 * 0.9 – 0.8 * 0.8)/1.7 = _________?

A. 0.1
B. 0.2
C. 0.3
D. 0.4
Explanation:
As numerator is of the form a2 – b2 = (a + b) (a – b), so the given expression simplifying becomes
(0.92 – 0.82)/(0.9 + 0.8) (0.9 + 0.8) (0.9 – 0.8)/0.9 + 0.8 = 0.1

Read More (0.9 * 0.9 – 0.8 * 0.8)/1.7 = _________?
Basic Maths Mcqs | Mathematics Mcqs | Time and Work Mcqs

A and B can finish a work 30 days if they work together. They worked together for 20 days and then B left. A finished the remaining work in another 20 days. In how many days A alone can finish the work?

A and B can finish a work 30 days if they work together. They worked together for 20 days and then B left. A finished the remaining work in another 20 days. In how many days A alone can finish the work?

A. 70
B. 50
C. 40
D. 60
Amount of work done by A and B in 1 day = 1/30
Amount of work done by A and B in 20 days = 20 × (1/30) = 20/30 = 2/3
Remaining work – 1 – 2/3 = 1/3
A completes 1/3 work in 20 days
Amount of work A can do in 1 day = (1/3)/20 = 1/60
=> A can complete the work in 60 days

Read More A and B can finish a work 30 days if they work together. They worked together for 20 days and then B left. A finished the remaining work in another 20 days. In how many days A alone can finish the work?
Mathematics Mcqs | Mensuration

Find the area of trapezium whose parallel sides are 20 cm and 18 cm long, and the distance between them is 15 cm.

Find the area of trapezium whose parallel sides are 20 cm and 18 cm long, and the distance between them is 15 cm.

A. 225 cm2
B. 275 cm2
C. 285 cm2
D. 315 cm2
Area of a trapezium = 1/2 (sum of parallel sides) * (perpendicular distance between them) = 1/2 (20 + 18) * (15) = 285 cm2

Read More Find the area of trapezium whose parallel sides are 20 cm and 18 cm long, and the distance between them is 15 cm.

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