Question

I have a total of Rs 300 in coins of denominations Re 1, Rs 2 and Rs 5.The number of Rs 2 coins is 3 times the number of Rs 5 coins.The total number of coins is 160.How many coins of each denominations are with me?

Answer 1

Suppose the number of Rs.5 coins are x.
Then number of Rs.2 coins = 3x
Total number of coins = 160
Then number of Re 1 coins = 160 - (x + 3x) = 160 - 4x
So total money = $5x+2\times 3x+\left(160-4x\right)=\mathrm{Rs}.300$
$$\begin{gathered} \Rightarrow 5x+6x+160-4x=300 \\ \Rightarrow 7x=140 \\ \Rightarrow x=20 \end{gathered}$$
Therefore number of Rs.5 coins = 20
Number of Rs.2 coins = $3\times 20=60$
And number of Re 1 coins = $160-20\times 4=80$