Welcome to Test-paper.info
Wednesday, December 13 2017 @ 04:51 PM CST
 Select a Forum » General Chat » Primary 1 Matters » Primary 2 Matters » Primary 3 Matters » Primary 4 Matters » Primary 5 Matters » Primary 6 Matters » Question, Feedback and Comments » Education Classified
 Forum Index >  Test Paper Related >  Primary 6 Matters Average question
 | Printable Version
 By: drstevewu (offline)  Wednesday, April 06 2016 @ 11:02 AM CDT (Read 1845 times)
drstevewu

1. The average score of all the children in a class for a test is 83 marks. The average score of all the 10 girls in the class is 90 marks. The average score of the boys is 78 marks.
(i) How many boys are there in the class?
(ii) Find the difference in the total scores between the boys and the girls?

Thank you,

Junior

Registered: 04/20/10
Posts: 31

 By: echeewh (offline)  Thursday, April 07 2016 @ 12:51 AM CDT
echeewh

Hey <drstevewu>,

Following is my worked solution:

Let the number of boys be 1u.

Total number of children (Boys + Girls) = u + 10

Total marks of all children = (u + 10) × 83
= 83u + 830 -- (1)

Total marks of all boys (B ) = (u) × 78 = 78u

Total marks of all girls (G) = 10 × 90 = 900

B + G = 78u + 900 -- (2)

But (1)=(2), hence ...

83u + 830 = 78u + 900
83u - 78u = 900 - 830
5u = 70
u = 14

(i) 14 boys

(ii)
B - G (scores) = 78u - 900
= (78 × 14) - 900 = 1092 - 900
= 192

=======

Trust this helps.

Do let me know again if this is different from your <Anskey> or if there's further clarification.

Cheers,
Edward

Active Member

Registered: 04/21/11
Posts: 627

 By: drstevewu (offline)  Sunday, April 10 2016 @ 07:33 PM CDT
drstevewu

Thank you very much Edward.

Junior

Registered: 04/20/10
Posts: 31

 All times are CST. The time is now 04:51 pm.
 Normal Topic Locked Topic Sticky Topic
 New Post Sticky Topic w/ New Post Locked Topic w/ New Post
 View Anonymous Posts Able to Post HTML Allowed Censored Content