Advertisement

### Question

In a sample there are 1440 items having a value of 50°C. 20% values are below 50°C, and the number of values above 50°C is $2/3$ of the items having a value of 50°C. What is the size of the sample?

**A**

3000 items.

**B**

3010 items.

**C**

2990 items.

**D**

3020 items.

**Soln.**

**Ans: a**

The %age ≥ 50°C = (100 - 20) = 80. If x is the size of the sample, 80% of x = 1440 + $2/3 × 1440$ = ${5 × 1440}/3$, which is same as ${80 × x}/100$ = ${5 × 1440}/3$. Solving, we get x = 3000.