SOLUTION: In a test, all questions were fo equal value. If you answered 9 of the first 10 questions correctly, but only 3/10 of the remaining questions correctly, you would have scored 50 pe

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: In a test, all questions were fo equal value. If you answered 9 of the first 10 questions correctly, but only 3/10 of the remaining questions correctly, you would have scored 50 pe      Log On


   

Question 1110397: In a test, all questions were fo equal value. If you answered 9 of the first 10 questions correctly, but only 3/10 of the remaining questions correctly, you would have scored 50 percent for the whole test. Find the number of questions in the test.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
In a test, all questions were of equal value.
If you answered 9 of the first 10 questions correctly, but only 3/10 of the remaining questions correctly, you would have scored 50 percent for the whole test.
Find the number of questions in the test.
:
let x = number of questions on the test
use .3 for 3/10
:
%28.3%28x-10%29%2B9%29%2Fx = .50
.3x - 3 + 9 = .5x
-3 + 9 = .5x - .3x
6 = .2x
x = 6/.2
x = 30 questions on the test
:
:
See if that works
.3(30-10) + 9 =
.3(20) + 9
6 + 9 = 15 which is 50%