Explanation

Given:

1. Ten years ago, C's mother was 4 times as old as C:

10 years ago, C = 15 → mother = 4×15 = 60 → Now = 70

After 10 years, mother = 80 → 2×25 = 50

Explanation

Find HCF of 408, 468, and 516

• Prime factorizations:

  • 408 = $2^3\cdot 3<br>$

  • 468 = $2^2 cdot 3 cdot 13$
    

  • 516 = $2^2\cdot 3\cdot 43$

Common: 2^2.3 = 4.3=12

Explanation

Given numbers:
0.1, 0.21, 0.31, 0.41, 0.51

Step 1: Add all the numbers

$$0.1 + 0.21 + 0.31 + 0.41 + 0.51 = 1.54$$

Step 2: Divide by the number of values

$$frac{1.54}{5} = 0.308$$

Explanation

• Price of 2½ dozens eggs = Rs. 75

• 1 dozen = 12 eggs

So:

2x1​/2 dozens=2.5×12=30 eggs

Now find the price of one egg:

$$text{Price of 1 egg} = frac{75}{30} = text{Rs. 2.50}$$

Explanation

Amount saved = 24

Percentage saved = 37.5% = 0.375

Weekly salary = Amount saved / Percentage saved

= 24 / 0.375

= 64