## Q&A - PSLE Math

Academic support for Primary 6 and PSLE
2632parent
OrangeBelt
Posts: 92
Joined: Sat Apr 07,

### Re: Q&A - PSLE Math

Need help on the following question

1. Anna and Ben take 9 days to complete a jigsaw puzzle. Ben and Celine take 3 days to complete the same jigsaw puzzle. When Celine partners Dennis, they take 4 days to complete the jigsaw puzzle. How many days will Anna and Dennis take to complete 2 such jigsaw puzzles?

S-H
BrownBelt
Posts: 564
Joined: Mon Feb 08,
Total Likes:1

### Re: Q&A - PSLE Math

MathIzzzFun wrote:
4. B and A have to paint a flat. B can paint twice as fast as A. They will take a total of 8hrs to paint the entire flat. How long will B take to paint the whole flat if he paints the house by himself ?
Workrate for A --> 1 unit/hour
Workrate for B --> 2 units/hour
Total when both work together --> 3 units/hour
in 8 hours, work completed --> 8 x 3 units/hour = 24 units

time taken for B to complete 24 units of work = 24 / 2 = 12 hours.

cheers.
Kindly please explain why 24/2 (time taken for B to complete 24 units of work) ?

acehkr3009
OrangeBelt
Posts: 42
Joined: Tue Mar 24,

### Re: Q&A - PSLE Math

Hi all,

Will need help to solve this problem...

Thanks.

acehkr3009
OrangeBelt
Posts: 42
Joined: Tue Mar 24,

### Re: Q&A - PSLE Math

Hi all,

Will need help to solve this problem...

Thanks.

acehkr3009
OrangeBelt
Posts: 42
Joined: Tue Mar 24,

### Re: Q&A - PSLE Math

Hi all,

Will need help on finding the area of the unshaded triangle.

Thanks.

KiasuNewbie
Posts: 8
Joined: Tue Jan 17,

### Re: Q&A - PSLE Math

Pls help

Mr Lee bakes 185 more chicken pie than tuna pie. After selling 3/5 Of the chicken pie and half of the tuna pies, he had 146 pie left. How many pie did he left?

MathIzzzFun
KiasuGrandMaster
Posts: 2357
Joined: Wed Mar 09,
Total Likes:5

### Re: Q&A - PSLE Math

S-H wrote:
MathIzzzFun wrote:
4. B and A have to paint a flat. B can paint twice as fast as A. They will take a total of 8hrs to paint the entire flat. How long will B take to paint the whole flat if he paints the house by himself ?
Workrate for A --> 1 unit/hour
Workrate for B --> 2 units/hour
Total when both work together --> 3 units/hour
in 8 hours, work completed --> 8 x 3 units/hour = 24 units

time taken for B to complete 24 units of work = 24 / 2 = 12 hours.

cheers.
Kindly please explain why 24/2 (time taken for B to complete 24 units of work) ?
B's work rate -> 2 units/hour
To complete 24 units of work, B will take 24 units ÷ 2 units/hour = 12 hours.

Alternatively, we can also work it this way:
Since B works twice as fast as A,
when A completed 1 flat, B would complete 2 flats over the same time--> total 3 flats.

A & B take 8h to complete 1 flat.
So, to complete 3 flats, they will take 3 x 8h = 24h
So, in 24h,
A completed 1 flat
B completed 2 flats --> 1 flat in 12 hours.

cheers.

Oldschool
GreenBelt
Posts: 139
Joined: Fri Mar 22,

### Re: Q&A - PSLE Math

acehkr3009 wrote:Hi all,

Will need help on finding the area of the unshaded triangle.

Thanks.

Hi,

Can you find the area of triangle from here?

Regards

MathIzzzFun
KiasuGrandMaster
Posts: 2357
Joined: Wed Mar 09,
Total Likes:5

### Re: Q&A - PSLE Math

Mr Lee bakes 185 more chicken pie than tuna pie. After selling 3/5 Of the chicken pie and half of the tuna pies, he had 146 pie left. How many pie -> chicken or tuna, did he left?
...missing word in question ? --> How many tuna pies or chicken pies left ?

At first,
Tuna pies --> 10u (LCM of 5 & 2) ... 1/2 --> 5u
Chicken pies --> 10u + 185 ... 3/5 --> 6u + 111

Pies left:
Tuna pies --> 5u
Chicken pies --> 4u + 74

Total --> 146

5u + 4u + 74 --> 146
9u --> 72
1u --> 8

chicken pies left --> 4 x 8 + 74 = 106
tuna pies left --> 40

cheers.

mikyway
GreenBelt
Posts: 138
Joined: Thu Nov 19,

### Re: Q&A - PSLE Math

Hi, pls help to solve this question:
In primary 6A, the average score for a math test was 71. The average score of all the girls in the class was 77 while the average score for all the boys was 63. There were 6 more girls than boys. How many pupils in the class?

TIA