
By: geniuskids (offline) Monday, October 15 2012 @ 10:21 PM CDT (Read 840 times)



geniuskids 
Help needed urgently:
Q9 : Sean had twice as much money as his brother, George. After George spent $20 and Sean received another $50 from their mother, Sean had five times as much money as George. How much money did Sean have at first?
Answer is 100
Q14 : Aaron and Ben shared a sum of $200. Aaron gave 3/5 of what he has to Ben. Ben later gave 1/5 of what he has back to Aaron. They ended up with equal amount amount of money. How much did Aaron have at first?
Answer is $187.50
Thanks

Active Member
Registered: 11/12/11 Posts: 169





By: echeewh (offline) Friday, October 19 2012 @ 11:26 PM CDT



echeewh 
hey there,
Following pls find my worked solutions:
Q9
<Before>
S 
G 
<Process>
S: +50
G: 20
<After>
**< 5u >
S < 50 >
G <20>
**<1u> <1u+20>
Apply <Gap & Difference> method,
5u  2u > 20 + 20 + 50
3u > 90
1u > 30
S (at first) = 5u  50 > (5 × 30)  50
= 150  50
= 100
=======================================
Q14
Apply <work backwards> method starting from the point
where both A,B had equal amounts.
<After>
B gave (1/5) to A, so B left with (4/5) or 4 parts. Hence, split B into 4 equal parts (p). Likewise, A = 4p.
A 
B 
<process>
A:  1p
B: + 1p
<Before>
A  > 3p
B  > 5p
<Before1>
A gave (3/5) to B, so A left with (2/5) or 2 units (u). Hence, multiply A by 2x > 3p × 2 > 6u.
Likewise, multiply B by 2x > 5p × 2 > 10u.
A: (2/5) > 6u
(5/5) > 6u × (5/2) = 15u
A: + 9u
B:  9u
A  > 15u
B  > 1u
Given that A,B shared $200 at first,
A + B = 200
15u + 1u > 200
16u > 200
1u > 200 ÷ 16 = 12.50
A (at first) = 15u > 15 × 12.50 = $187.50
=========================
Trust the above helps.
Do let me know again if there's further clarification.
Cheers,
Edward

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





By: geniuskids (offline) Saturday, October 20 2012 @ 04:06 AM CDT



geniuskids 
Thanks again Edward, managed to handle these!.

Active Member
Registered: 11/12/11 Posts: 169



