Quiz!

Algebra Level 2

A quiz has thirty questions whose answers can only be correct or incorrect.

A correct answer scores 8 points, but 3 points are deducted for every incorrect answer.

Harry did the quiz and scored a total of 152 points. How many questions did he get correct?


Try this: All of my problems


The answer is 22.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Munem Shahriar
Aug 8, 2017

Suppose Harry got x x correct answers and y y incorrect answers.

For the x x correct answers, he scored 8 x 8x points

For the y y incorrect answers, 3 y 3y points were deducted.

So, Harry's score = ( 8 x 3 y ) = (8x - 3y) points.

But we are told Harry scored a total of 152 152 points.

8 x 3 y = 152.......... ( 1 ) 8x -3y = 152 .......... (1)

We also know there were 30 30 questions altogether

x + y = 30.......... ( 2 ) x + y = 30.......... (2)

Multiply ( 2 ) (2) by 3 : 3:

8 x 3 y = 152......... ( 1 ) 8x - 3y = 152 ......... (1)

3 x + 3 y = 90......... ( 3 ) 3x + 3y = 90 ......... (3)

Add equations ( 1 ) (1) and ( 2 ) : (2):

11 x = 242 11x = 242

x = 22 x = \color{#3D99F6} \boxed{22}

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...