2017 · Q40
Sunil wants to spend ₹ 200 on two types of sweets, costing ₹ 7 and ₹ 10 respectively. What is the maximum number of sweets he can get so that no money is left over ?
Elementary MathematicsNumber System
- A25
- B26
- C27
- D28
Explanation
7x + 10y = 200 with x, y non-negative integers. Then 7x ≡ 0 (mod 10), so x ∈ {0, 10, 20}, giving totals 20, 23, 26 sweets. The maximum is 26 (x = 20, y = 6): option B.