Q&A - PSLE Math

[zanen]

Zhu99:

zanen:

Hi thanks for the previous ans. can help me with these two. thx in advance A rabbit and a tortoise competed in a 5.2 km race. The rabbit ran at a speed of 20 km/h while the tortoise’s speed was 3 km/h. The tortoise ran continuously to complete the race. However the rabbit ran for 1 min and rested for 20 min. It ran the next 2 min and rested or 20 min. It then ran for the next 3 min and rested for 20 min and so forth. At this rate, how many minutes more would it take the rabbit than the tortoise to complete the race?

T : 5.2/3 x 60 = 104 min

R : 5.2/20 x 60 = 15.6 min --- run time

1 + 2 + 3 + 4 + 5 + 0.6 ---> 5 rest time
5 x 20 = 100

100 + 15.6 = 115.6 min --- total time of R

115.6 - 104 = 11.6

The rabbit took 11.6 min more than the tortoise to complete the race.

May I know why 5 rest time and not more? :scratchhead:

[tianzhu]

jonaandr:

3. Katy had a number of 20-cent coins and Jeremy had a number of 50-cent coins. Katy had 18 more coins than Jeremy but Jeremy had $8.10 more than Katy. express, to the nearest percent, the amount of money Katy had as a percentage of the amount of money Jeremy had.

Hi

Please study this solution for a similar type of question. It should help to answer your question.

I did a quick check for your question and there are 57 number of 20-cent coins and 39 number of 50-cent coins. I’ll leave you to work out the rest of the details.

Best wishes

http://farm6.staticflickr.com/5014/5557734869_1bdc3c4e23_z.jpg\">

[tianzhu]

jonaandr:

4.alicia and Bruce are given some money each. If Alicia spends three times as much as Bruce,She will have $1000 more when Bruce has spent all his money. If alicia spends half of what Bruce spends, she will have $2200 when Bruce has spent all his money. What is the total sum of money given to Alicia and Bruce?

Hi

Please study this solution for a similar type of question. It should help to answer your question.

For your question, the answers are $2440 for Alicia and $480 for Bruce. I’ll leave the rest of the details to you.

Best wishes

http://farm6.staticflickr.com/5142/5614468685_555807d62e_z.jpg\">

[zanen]

mind helping with this question? thankyou. :)There is a big migic fruit tree in a garden. It bears fruits at a constant rate every day. Man will pick the fruits and sell. Animals will pluck and eat the fruits. 25 men can pick all the fruits in 15 days and 66 animals can eat all the fruits in 10 days. If 1 man can pick twice the number of fruits as 1 animal, find the number of days it take for 10 men to pick and 10 animals to eat all the fruits together?

[ms_lim]

Can help to explain how to solve this question?


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[tianzhu]

zanen:

mind helping with this question? thankyou. :)There is a big migic fruit tree in a garden. It bears fruits at a constant rate every day. Man will pick the fruits and sell. Animals will pluck and eat the fruits. 25 men can pick all the fruits in 15 days and 66 animals can eat all the fruits in 10 days. If 1 man can pick twice the number of fruits as 1 animal, find the number of days it take for 10 men to pick and 10 animals to eat all the fruits together?

Hi

Is this a PSLE type of question?

The answer to this question is 40 days.

Best wishes

[Zhu99]

zanen:

Zhu99:

[quote=\"zanen\"]Hi thanks for the previous ans. can help me with these two. thx in advance A rabbit and a tortoise competed in a 5.2 km race. The rabbit ran at a speed of 20 km/h while the tortoise’s speed was 3 km/h. The tortoise ran continuously to complete the race. However the rabbit ran for 1 min and rested for 20 min. It ran the next 2 min and rested or 20 min. It then ran for the next 3 min and rested for 20 min and so forth. At this rate, how many minutes more would it take the rabbit than the tortoise to complete the race?

T : 5.2/3 x 60 = 104 min

R : 5.2/20 x 60 = 15.6 min --- run time

1 + 2 + 3 + 4 + 5 + 0.6 ---> 5 rest time
5 x 20 = 100

100 + 15.6 = 115.6 min --- total time of R

115.6 - 104 = 11.6

The rabbit took 11.6 min more than the tortoise to complete the race.

May I know why 5 rest time and not more? :scratchhead:[/quote]The rabbit ran for 15.6 mins.
1 + 2 + 3 + 4 + 5 + 0.6 = 15.6 --- The '+\" basically represents the rest time (period). As there are 5 '+\"s, there are 5 rest time (periods). To have the 6th rest time, the balance time should be 6 min. But the rabbit completed the race with balance 0.6 min.

[Zhu99]

zanen:

Mrs Reuten bought some pizzas for a group of children. The girls received thrice as many pizzas as the boys. There were an equal number of girls and boys. Each boy ate 2/9 of a pizza and the boys finished all the pizzas given to them. Each girl ate 1/6 of a pizza and the girls had 4½ pizzas left. How many pizzas did Mrs Reuten buy?

Pizzas received --- G : B = 3 : 1
= 3 x 4 : 1 x 4
= 12 : 4 --- To get 4 for B since boys finished all the pizzas given

Pizzas eaten --- B : G = 2/9 : 1/6 --- Equal number of girls and boys
= 2/9 x 9 : 1/6 x 9
= 2 : 3/2
= 2 x 2 : 3/2 x 2
= 4 : 3

12 - 3 = 9 u ---> 4 1/2

12 + 4 = 16 u --> 16/9 x 4 1/2 = 8

Mrs Reuten bought 8 pizzas.

[ms_lim]

Can help to explain how to solve this question?


http://i48.tinypic.com/14r7mv.jpg\">

[Winx5015]

Hi, anyone can help me with the following questions.


(1). A train left Station X with some commuters. At the first stop, no commuters alighted and the number of commuters who boarded the train was 1/5 of the original number of commuters in the train. At the second stop, 1/4 of the commuters alighted and 58 commuters boarded the train. At the third stop, 3/7 of the commuters boarded the train. At the last stop, all 315 commuters alighted. How many commuters were there when the train left Station X?

(2). Mother baked some square, round and oval cookies. For every 3 square cookies that were baked, 2 round cookies were baked. For every 4 square cookies that were baked, 3 oval cookies were baked.
(a). Find the ratio of the number of square cookies to round cookies to oval cookies baked.
(b). After mother baked another 120 round cookies, 30% of the cookies now were round cookies. How many square cookies did the bakery bake?

(3). Hadi had 295 more sweets than Ravi. After Hadi had given away 2/5 of the sweets he had and Ravi gave away 2/3 of the sweets he had, Hadi had 329 more sweets than Ravi. How many sweets did they have altogether at first?

Thank you