Question #016ba

2 Answers
Sep 4, 2017

Answer:

#3/17# of a gallon of water

Explanation:

A solution that is #85%# antifreeze means it is in the ratio:

Antifreeze : water

#85% : 15%" "larr# this simplifies to

#17:3#

Use direct proportion:

#(1 "gallon")/(17) = x/(3)#

#x = (1 xx 3)/17# gallons

#x = 3/17# of a gallon of water must be added.

Sep 4, 2017

Answer:

Another approach just for the hell of it!

#3/17# gallons #~~0.1765# gallons to 4 decimal places

Explanation:

We know that we are going to use all of the 1 gallon of antifreeze.

The target concentration is 85%

Let the final volume of the blend be #x#

Then 85% of #x = 1" gallon"#

Thus we have

#85/100x=1#

#x=1xx100/85" "# this is water + antifreeze

so the amount of added water is:

#100/85 - 1color(white)("ddd")->color(white)("ddd")100/85-85/85#

#=15/85color(white)("dddd")->color(white)("ddddd")(15-:5)/(85-:5)color(white)("ddd") =color(white)("d") 3/17# of a gallon

#~~0.1765# gallons to 4 decimal places