Q&A - PSLE Math

[doraemo]

Thank you, Nebbermind & BigDevil !!!!

[doraemo]

hi, another one.

please help.

After hiking for 30km, Martin took break before he continued hiking 1/3 of the remaining distance. He then realised that he still had ¼ of the total distance not completed. If Martin’s average speed was 6 km/h , how much time did he take to complete the entire hike?

[AppleCrumble]

hi, another one.

please help.

After hiking for 30km, Martin took break before he continued hiking 1/3 of the remaining distance. He then realised that he still had ¼ of the total distance not completed. If Martin’s average speed was 6 km/h , how much time did he take to complete the entire hike?

Hope my solution is correct:

Total Distance -> 30 + u + u + u = 30 + 3u (deduce from first sentence)

u + u -> 1/4 of Total Distance (deduce from second sentence)
Total Distance -> 4 x 2u = 8u

So,

30 + 3u -> 8u

5u -> 30

1 u -> 6

Total distance -> 8 x 6 = 48

Time taken -> 48/6 = 8 hours

[doraemo]

Thank you, AppleCrumble!!!!

[SOS mum]

Hi, pls help. Many tks and God Bless:)

Harry paid $320 for 5 shirts and 2 pairs of pants. If he bought another shirt, he would have $15 left. If he bought another pair of pants, he would be short of $5. How much did Harry have?

[Sun_2010]

Hi, pls help. Many tks and God Bless:)

Harry paid $320 for 5 shirts and 2 pairs of pants. If he bought another shirt, he would have $15 left. If he bought another pair of pants, he would be short of $5. How much did Harry have?

one extra shirt would leave him with $15 excess
1Extra pants will leave him wit $5 shortage
So a pant costs $20 more than a shirt

cost of 5 shirts + 2 pants = cost of 5 shirts + 2 shirts +2x$20
= 7 shirts+$40

7 shirts+$40 = $320
1 shirt = $40
He has $320+$40 ( cost of extra shirt) + $15 ( his excess) = $375

[nicnac]

Hi, pls help. Many tks and God Bless:)

Harry paid $320 for 5 shirts and 2 pairs of pants. If he bought another shirt, he would have $15 left. If he bought another pair of pants, he would be short of $5. How much did Harry have?

Each pair of pants costs $20 more than each shirt.
If you Make shirt -> 1u, then pants -> 1u + 20

5u + ( 2u+ 40) -> 320
7u->280
U->40

He has : 320 + 40 + 15 -> $375

[BigDevil]

vvv
A: 1715860
Subject: Math
Level: P6
Tags:
Source:
^^^

[deon629]

Pls help. TIA.

Charlie had 148 pieces of $2 and $5 notes. She spent 60% of her $5 notes to buy a bag and then her mother gave her another six $2 notes. As a result, the number of $2 notes was thrice as many as the number of $5 notes left. Find the amount of money Charlie had left.

[EconsPhDTutor]

Pls help. TIA.

Charlie had 148 pieces of $2 and $5 notes. She spent 60% of her $5 notes to buy a bag and then her mother gave her another six $2 notes. As a result, the number of $2 notes was thrice as many as the number of $5 notes left. Find the amount of money Charlie had left.

Answer: $308.
Solution:

Let T and F be the initial numbers of $2 and $5 notes. We have

(1) T + F = 148.

After buying the bag, the number of $5 notes she has is 0.4 F.
After her receiving another six $2 notes, the number of $5 notes she has is T + 6.
We are told that she then has thrice as many $2 notes as $5 notes.

Thus,

(2) 3 × 0.4 F = T + 6.

From (1), we have T = 148 - F. Plug this into (2) to get

3 × 0.4 F = 148 - F + 6.

Rearranging, we have 2.2 F = 154, and thus F = 70.

So T = 78.

And so the money she has at the end of the day is

0.4 F × 5 + (T + 6) × 2 = 0.4 × 70 × 5 + (78 + 6) × 2 = 140 + 168 = $308.

Hope this helps and feel free to ask for any clarifications.

- Dr. Choo Yan Min


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