contestada

Melissa keeps a jar for holding change. The jar holds 21 coins. All of the coins are quarters and nickels. The total amount in the jar is $3.85. How many quarters are in the jar?

Respuesta :

rarrininger
q + n = 21
q = 21 - n

.25q + .05n = 3.85
.25(21 - n) + .05n = 3.85
5.25 -.25n +.05n=3.85
5.25 -.2n=3.85
5.25-5.25 -.2n =3.85-5.25
-.2n= -1.4
-.2n/-.2n= - 1.4/-.2
n=7

q = 21 - 7
q= 14

Check
.25q + .05n = 3.85
.25(14) + .05(7) = 3.85
3.5 + .35=3.85
3.85=3.85

Otras preguntas