Explanation

Total work = people × days = 500 × 25 = 12500 person-days

Work done in first 12 days by 500 people = 500 × 12 = 6000 person-days

Remaining work = 12500 - 6000 = 6500 person-days

Now 300 people will do the remaining work.  

Days needed = Remaining work / people = 6500 / 300 = 21⅔ days

Last verified on 05-09-2026

Explanation

Let son's age = x. Then mother's age = 3x because it is 3 times the son's age.

Sum of ages = 70, so x + 3x = 70 → 4x = 70.

Solve: x = 70 ÷ 4 = 17.5. So son's present age = 17.5 years

Last verified on 05-09-2026

Explanation

Let the son's present age = x years.

Mother's age = 5x years.

After 10 years:

5x + 10 = 3(x + 10)

5x + 10 = 3x + 30

2x = 20 → x = 10

Last verified on 06-09-2026

Explanation

Worker-days = Workers × Days

= 5 × 12 = 60 worker-days.

Last verified on 07-09-2026

Explanation

Let the son's age = x years

Mother's age = 5 times son's age = 5x years

Sum of their ages = 60 years

So, x + 5x = 60

6x = 60  

x = 60 / 6  

x = 10

Son's present age = 10 years

Last verified on 04-09-2026