Explanation

Combined work per day:

A = 1/12

B = 1/18  

C = 1/36

Together in 1 day:

1/12 + 1/18 + 1/36 = 3/36 + 2/36 + 1/36 = 6/36 = 1/6

If they do 1/6 of the task in 1 day, they do the full task in 6 days.

Last verified on 17-10-2026

Explanation

5 machines = 5 widgets in 5 minutes

So 1 machine = 1 widget in 5 minutes

100 machines will make 100 widgets in same 5 minutes (each machine makes 1)

Last verified on 12-10-2026

Explanation

Let A's present age = x

10 years ago:

Mother's age = 4 _ (x - 10)

After 10 years:

Mother's age = 2 _ (x + 10)

Difference between those two mother ages is 20 years:

4(x - 10) + 20 = 2(x + 10)

4x - 40 + 20 = 2x + 20

4x - 20 = 2x + 20

2x = 40

x = 20 years

Last verified on 12-10-2026

Explanation

• Speed = 12 km/h
• Time = 15 minutes = 15/60 = 1/4 hour

Formula:

Distance = Speed x Time 

= 12 x 1/4

$$= 12 times frac{1}{4}$$ =3 km

Explanation

Let the present age of the son = x years.

Present age of the father = 45 − x years.

5 years ago:

Father's age = 40 − x

Son's age = x − 5

According to the question:

40 − x = 6(x − 5)

40 − x = 6x − 30

70 = 7x

x = 10

Son's present age = 10 years.

Father's present age = 45 − 10 = 35 years.

Last verified on 08-10-2026