Q&A - PSLE Math

[jieheng]

shurley197323:

Thanks a lot , jieheng.

Hi shurley197323 ,

You are welcome .

Regards,

[jieheng]

peggy:

Help is needed here!


P5 qtn :

Vernice had $1196 more than Ethan. If Vernice were to give 1/7 of her money to Ethan, she would have 4 times as much as Ethan. How much money did Ethan have?

Thanks.

V [---------------][---------------][---------------][---------------]

E [---------------]

Vernice left 6/7 if she were to give 1/7 to Ethan , change [---------------] to [-------6u-----]

V [-------6u-----][-------6u-----][-------6u-----][-------6u-----]

E [-------6u-----]

6/7 ------> 24u , so 1/7 -----> 4u

V [-------6u-----][-------6u-----][-------6u-----][-------6u-----]

E [2u-][---4u---]

Transferred back 4u from E to V

V [-------6u-----][-------6u-----][-------6u-----][-------6u-----][---4u---] (28u)

E [2u-]

Vernice had $1196 more than Ethan ,

(28u - 2u) -----> 1196
26u -----> 1196
1u -----> 46

the amount of money that Ethan had = 2u = 2*46 = $92 (Ans)

[peggy]

Hi Jieheng,


Thanks for the solution. A little confused as to why (--------) can change to (----6u—)??

Thanks.

[jieheng]

peggy:

Hi Jieheng,


Thanks for the solution. A little confused as to why (--------) can change to (----6u---)??

Thanks.

As Vernice left 6 / 7 , if we change [---------------] to [-------6u-----] or (any multiples of 6) , we are able to know how many units is (1/7) that Vernice gave to Ethan .

Regards,

[peggy]

Got it! Thanks Jieheng.

[jieheng]

peggy:

Got it! Thanks Jieheng.

Hi peggy ,

You are welcome .

Regards,

[shurley197323]

Hi, pls help and sorry for asking so often.

(1) Alan had thrice as many oranges as mangoes. After he sold 136 oranges and threw away 12 rotten mangoes, the no of oranges left was the no of mangoes left. How many mangoes did he have left? (ans : 40)

(2) lynn order some balloons for a carnival. 2/7 of the ballon are gold. The rest of the ballons are silver,red and blue in the ratio of 6:3:11. There are 120 fewer gold balloons than blue balloons. How many silver ballon did lynn order?

[shurley197323]

Very sorry, 2 more questions to ask

(1) A salesman received a commission of $3 for every set of books he sold. For every 15 sets of books he sold, he will receive additional $15. How many sets of books did he sell if he receive a total commission of $216. (ans :57)

(2)To buy a story book.Gilbert started saving $0.40 every day.Helena starts saving 5 days after Gibert started and she saves $0.40 more than Gilbert every day.When Gibert saved enough money to buy the storybook.Helena had already saved $14 more than him.How much does Gilbert book cost? (ans:$18)

[CoffeeCat]

shurley197323:

Very sorry, 2 more questions to ask

(1) A salesman received a commission of $3 for every set of books he sold. For every 15 sets of books he sold, he will receive additional $15. How many sets of books did he sell if he receive a total commission of $216. (ans :57)

(2)To buy a story book.Gilbert started saving $0.40 every day.Helena starts saving 5 days after Gibert started and she saves $0.40 more than Gilbert every day.When Gibert saved enough money to buy the storybook.Helena had already saved $14 more than him.How much does Gilbert book cost? (ans:$18)

(1)
For every 15 sets of books he sold, he will receive additional $15.
This suggests we must first find out the total commission for every 15 sets of books. $15*3 + $15 = $60.
$216 / $60 = 3 r $36.
Hence there are 3 groups of 15 sets (45 sets) and $36/ $3 = 12 sets of books (57 in total).

(2)
To make easier comparison on a day-to-day basis (because we know Helena saved up more than Gibert), we must find out how much headstart Gibert has before Helena started saving : $0.40*5 = $2.

Despite having $2 headstart, Helena still end up with $14 more. This suggest after Helena started saving, she saved a total of $16 more than Gibert.
Helena thus saved for a total of $16/$0.40 = 40days.
Gibert saved for a total of 45 days.
Hence cost of book is 45*$0.40 = $18.

[HappyFaye]

shurley197323:

Hi, pls help and sorry for asking so often.

(1) Alan had thrice as many oranges as mangoes. After he sold 136 oranges and threw away 12 rotten mangoes, the no of oranges left was the no of mangoes left. How many mangoes did he have left? (ans : 40)

http://postimage.org/image/1wo2gxf5w/