The price of a brick today is 49 cents. This is 3 cents less than 4 times the price 20 years ago. What was the price 20 years ago?
1 Answer
Dec 11, 2017
Explanation:
#"let the cost of a brick 20 years ago "=c#
#rArr4c-3=49larrcolor(blue)"solve for c"#
#"add 3 to both sides"#
#4c cancel(-3)cancel(+3)=49+3#
#rArr4c=52#
#"divide both sides by 4"#
#(cancel(4) c)/cancel(4)=52/4#
#rArrc=13#
#"the cost of a brick 20 years ago was "13" cents"#
#color(blue)"As a check"#
#(4xx13)-3=52-3=49#
