<PRE><B>Question 1065017</B>
Brenda has save 300 coins,consisting of 25 centavo and 10 centavo coins.
If the total value of her savings is 45 pesos, how many 10 centavo coin did she save?
:
let a = no. of 25 cent coins
let b = no. of 10 cent
Write a equation for the total no. of coins and an equation for the value of the coins
a + b = 300
b = (300-a); use this form for substitution
and
.25a + .10b = 45
replace b with (300-a)
.25a + .10(300-a) = 45
.25a + 30 - .10a = 45
.25a - 10a = 45 - 30
.15a = 15
a = 15/.15
a = 100 ea 25 cent coins
therefore
300 - 100 = 200 ea 10 cent coins
:
;
Check this
100 *.25 = 25
200 *.10 = 20
---------------
Total$ = 45</PRE>