Question

A sum of rs. 350 made up of 110 coins, which are of either rs. 1 or rs. 5 denomination. how many coins are of rs. 5?

Answer 1

$x \times 1 + (110 - x) \times 5 = 350 \\ 4x = 200 \\ x = 50$
there are 60 coins of rs. 5