Question

A lady had only 50 paise and Rs. 1 coin in her purse The total number of coins was 120 and the total amount was Rs. 100. The number of RS 1 coins is __________,
1. 60
2. 70
3. 80
4. 90

Answer 1

Correct Answer - Option 3 : 80

Given 

Total number of coin = 120 

Total amount = Rs 100 

Calculation 

Let the number of coins of 50 p and Re 1 be x and y 

According to question 

x + y = 120       ----(1)

x/2 + y = 100      ----(2) 

Subtract equation (2) 

By solving (1) and (2) from equation (1)

⇒ x - x/2 = 120 - 100

⇒ x/2 = 20

We get x = 40 and y = 80 

So number of coins of Rs 1 = 80 

∴ The required answer is 80