SAT has these kinds of Questions?

Question

2. If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?

How do you solve these problems algebraically, this test is designed to make me feel stupid.

Answer 1

First you must find how much each of them can do in 1 hr. so sally can do 1/4 of the house in one hour and john 1/6 of the house in one hour. Since they both have to work together you must add each one multiplied by the time they both worked. So (1/4)x+(1/6)x=1 which is 5/12(x)=1 and then isolate the x and you get 12/5 or 2.4.

Also if you really need help on ur sat math then get the barrons How to prepare for the SAT and read throught the math and do the problems...it explains everything. I brought my score from a 630 to a 750 in less than a month.

Answer 2

Answer: 12/5 hrs

1/6 + 1/4 = 1/x

10/24 = 1/x

5/12 = 1/x

x = 12/5