Question

a man has only 20 paisa and 25 paisa coins in his purse.If he has 50 coins in all totalling 11.25rs,how many coins of each kind does he have

Answer 1

he have twenty five 20 paisa coins and twenty five 25 paisa coins.
20p×25=rs 5.
25p×25=rs 6.25.
therefore total = rs 11.25

Answer 2

$\bold \color{green} { \underline { \underline \red{ \green\star \: required \: answer}}} \star$

Let the number of 20 paisa coins be x and that of 25 paisa coins be y. then,

$\bold{x + y = 50}$

total value of 20 paisa coins = 20x paisa

total value of 25 paisa coins = 25y paisa

$\bold{so \: that \: \: 20x + 25y = 1125 }\\ \bold{ \implies4x + 5y - 225 = 0}$

now by using corss-multiplication, we have

$\bold{\frac{x}{ - 225 + 150} = \frac{ - y}{ - 225 + 20} = \frac{1}{5 - 4} }$

$\bold{\implies \frac{x}{25} = \frac{y}{25} = \frac{1}{1}}$

$\bold{\implies \: x = 25 \: \: and \: y = 25}$

hence, there are 25 coins of each kind..