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my average score on 8 math test is 90. If my average  on the first 5 test was 87, what was my avergae score on the last 3 test?

 Jan 18, 2019
edited by CDorrell  Jan 18, 2019
 #1
avatar+111357 
+2

360°

 

To see this....draw a diagonal connecting any pair of opposite vertices

 

This will split the trapezoid into two triangles....

 

The interior angles of each triangle will sum to 180°

 

So  ...2 * 180°  =  360°

 

 

cool cool cool

 Jan 18, 2019
 #2
avatar+111357 
+1

Mmmmmm.....the question seems to have changed....LOL!!!

 

We need  8 *90  = 720 points on the 8 tests

 

So

 

720 -  5(87)  = 285 remaining

 

So....we need to average

 

285 /3   =   95  on the last three

 

 

cool cool cool

 Jan 18, 2019

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