+0  
 
0
107
1
avatar

Dorris's average mark out of three tests was 82. Her last mark was 3/2 times her first mark. The middle mark was 86. What was the difference between Dorris's first and last marks?

Guest Apr 22, 2017
Sort: 

1+0 Answers

 #1
avatar
0

Let her 1st mark =M, then:

 

M + 86 + 3/2M =3 x 82=246, solve for M

M = 64 - Her 1st mark

64 x 3/2 =96 - Her last mark, so that:

64 + 86 + 96 =246/3 =82 - Her average mark.

Guest Apr 22, 2017

22 Online Users

avatar
avatar
avatar
avatar
avatar
avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details