
By: lbselaine (offline) Tuesday, August 14 2012 @ 08:46 AM CDT (Read 896 times)



lbselaine 
Hi,
Can someone kindly teach me how to solve this qns? I need to teach my son who have problem solving it.
Qns:
Tom had 20% more marbles than Gary.
Billy had 25% fewer marbles than Tom.
If Billy and Gary had 1520 marbles, how many marbles did the 3 boys have altogether?
Thanks in advance.

Newbie
Registered: 12/31/06 Posts: 2





By: echeewh (offline) Tuesday, August 14 2012 @ 09:19 PM CDT



echeewh 
Hey Elaine
Following pls find my worked solution:
Since T had 20% more than G, this means T had 120% compared to T (who had 100%). In ratio format, we have ...
T : G
120 : 100
Given B had 25% fewer than T, this means B had 75% compared to T (who had 100%). From above ratio, T had 120u. So we have ...
(T) 100% > 120u
(B ) 75% > (120/100) x 75 = 90u
So the ratio will be as follows:
T : G : B
120 : 100 : 90
12 : 10 : 9
Given B+G = 1520 marbles, we have ...
B+G = 9u + 10u > 1520
19u > 1520
1u > 80
Hence, total (T+G+B ) = 12u + 10u + 9u = 31u
31u > 31 x 80 = 2480
Total marbles of the 3 boys = 2480
================
Trust this helps
Do let me know again if this does not match your Answerkey or if theres any clarification.
Cheers,
Edward

Active Member
Registered: 04/21/11 Posts: 623





By: lbselaine (offline) Sunday, August 19 2012 @ 08:17 PM CDT



lbselaine 
Hi Edward,
Thanks for the detail explanation.
I took the incorrect ratioas :
T = 120
G = 100
B = (12025) = 95 which is incorrect.
Regards,
Elaine

Newbie
Registered: 12/31/06 Posts: 2



