
By: JessicaTan (offline) Thursday, March 14 2013 @ 07:36 AM CDT (Read 1195 times)



JessicaTan 
Please help with working solution.
12) Ali & Bala earned an average of $486 last week. This week, Ali's earnings increased by 20% while Bala's earnings increased by 50%. After this increase, both Ali & Bala earned the same amount. What is Ali's earnings for this week?
Rdgs

Regular Member
Registered: 10/17/09 Posts: 82





By: echeewh (offline) Thursday, March 14 2013 @ 04:59 PM CDT



echeewh 
Hi Jessica,
As this question comes from a past year paper, it will be much appreciated if you can also indicate the name of the school (if possible) so that we can confirm our answer with the Answerkey. Alternatively , pls indicate the Answerkey here as well. Thanks.
Following is my worked solution:
Q12
<This Week>
A: 120% = (12 / 10) = (6 / 5)
B: 150% = (15 / 10) = (3 / 2)
Given that A's earnings = B's earnings, we have ...
(6 / 5) A = (3 / 2) B
Applying <Equal Concept>, multiply (3 / 2) by (2 / 2) to make numerator for B the same as A.
(6 / 5) A = (6 / 4) B
Hence, at first (Last week) , A = 5u; B = 4u
<Last week>
Given that average earning is $486,
Total (A + B ) earnings = 486 × 2 = 972
9u > 972
1u > 108
Hence, A's earnings (this week) = 6u > 6 × 108 = $648
==============
Trust this helps.
Do let me know again if this is different from the Answerkey or if there's further clarification.
Cheers,
Edward

Active Member
Registered: 04/21/11 Posts: 627





By: JessicaTan (offline) Friday, March 15 2013 @ 03:56 AM CDT



JessicaTan 
Thanks for your working, Edward.
This question comes from De La Salle. I do not have the correct answer. Sorry for your inconvenient.
Rdgs
Jessica

Regular Member
Registered: 10/17/09 Posts: 82



