Question

A sum of Rs. 8.75 is made up of 105 coins, which are either 10 paise or 5 paise. How many 5 paise coins are there?

• A. 40
• B. 38
• C. 37
• D. 35

Hint:

To save time, assume all 105 coins are 10p. The total would be 1050p. The difference from the actual total (1050 - 875 = 175p) is caused by the 5p coins. Divide this difference by the gap between coin values (5p): \(175 / 5 = 35\).

Answer 1

The Correct Option is D

Concept:
Step 1: Set up equations.
Let \(x\) be 5p coins and \(y\) be 10p coins.
\(x + y = 105\)
\(5x + 10y = 875\) (Converting Rs to paise).

Step 2: Solve for \(x\).
Divide the second equation by 5: \(x + 2y = 175\).
Subtracting the first: \((x + 2y) - (x + y) = 175 - 105 \Rightarrow y = 70\).
\(x = 105 - 70 = 35\).