Question

Maria has 7euro in coins of 20 and 50 cents. If in total have 23 coins,how are of each type?​

Answer 1

Respuesta:

María has 8 coins of 50 cents and 15 coins of 20 cents

Explicación paso a paso:

If "x" are the total coins of  20 cents and "y" the amount of coins of 50 cents

x + y = 23

x = y - 23

also

0.20 x + 0.50 y = 7

we replace "x"

0.20 ( y - 23 ) + 0.50 y = 7

4.6 - 0.20 y + 0.50 y = 7

- 0.20y + 0.50 y = 7 - 4.6

0.30y = 2.4

y = 2.4 / 0.30

y = 8   ( coins of 50 cents )

we calculate "y"

y = 23 - 8

y = 15  ( coins of 20 cents )