Q&A - PSLE Math

[tianzhu]

Michaelia0816:

Help again with the following 3 questions!!!!!!


The diagram shows the road linking town p to town q.
P to q distance is 280km!
Roy passed P at 10am and reached q at 2 pm. Sam drove from p to q at a constant speed of 100km/h and arrived at a at 1.48pm.
a) when did Roy leave p?
b) when Sam reached town q, how far away from town q was Roy?

Hi

I don’t get to see the diagram, but based on your description, I’ll attempt to answer your question.

280/100 ------ 2.8h -------2h 48 minutes

(a)Roy left P at 10 am

Roy’s speed ------ 280/4 -------70km/h

Roy was 12 minutes away

12/60* 70 ------ 14 km

Best wishes

[tianzhu]

Hi Michaelia0816


Good morning, girl

I wish to heighten awareness that you’ve been posting too many questions.

I’ve raised this earlier. Are you having difficulties understanding them or just wanted to check the answers?

Perhaps your school teacher has just started out on the topic on Speed. Those questions you posted might be beyond your readiness. This may cause you to be unduly anxious as you are unable to cope.

If you are really having problems understanding the Speed concepts, may I suggest you approach your school teacher to straighten them out.

Understanding the basics and building up a firm foundation is the key to enhance your ability to cope with questions in the examinations.

Best wishes

[Michaelia0816]

Thank for the 3 questions! Now I can focus on the exam tomorrow!

[tianzhu]

Michaelia0816:

Thank for the 3 questions! Now I can focus on the exam tomorrow!

Hi

You're welcome.

Wishing you the very best for your exam.

Best wishes

[parents222]

Please help with this speed question and many thanks in advance…


Amy and Betty ran in a race. When Amy has completed 7/8 of the distance, Betty had only completed 2/3 of the distance of the race.

Amy’s average speed for the race was 80m/min faster than Betty’s. What was Betty’s average speed for the race in m/min?

[Michaelia0816]

tianzhu:

Michaelia0816:

Thank for the 3 questions! Now I can focus on the exam tomorrow!

Hi

You're welcome.

Wishing you the very best for your exam.

Best wishes

Thank!

[tianzhu]

parents222:

Please help with this speed question and many thanks in advance...


Amy and Betty ran in a race. When Amy has completed 7/8 of the distance, Betty had only completed 2/3 of the distance of the race.

Amy's average speed for the race was 80m/min faster than Betty's. What was Betty's average speed for the race in m/min?

Hi

As in any questions on Speed, it’s useful to start with a simple diagram.

A common multiple of 3 and 8 is 24

First consider the distance ratio.

Amy ------- 21 units
Betty ------ 16 units

Speed and distance are in direct proportion to each other.

Amy covered more distance than Betty during the same period; this means her speed is higher than Betty.

21 – 16 -------5

5 units ------- 80

1 unit -------- 16

Betty’s speed -------- 16*16 ------- 256 m/min

Best wishes

[parents222]

Hi tianzhu, now I understand and it seems simple too! Thank you very much for your time!!

[parents222]

Please help with this ratio question and many thanks in advance…


At a carnival, there were 40% more males than females. There was an equal number of males without caps to the number of females without caps. The number of males with caps to the number of female with caps was 6:2.

a. What was the ratio of the number of females with caps to the number of females without caps?

b. Midway, 800 females left the carnival. In the end, there were 3/7 as many females as males remaining behind. How many people were at the carnival at first?

[tianzhu]

parents222:

Please help with this ratio question and many thanks in advance...


At a carnival, there were 40% more males than females. There was an equal number of males without caps to the number of females without caps. The number of males with caps to the number of female with caps was 6:2.

a. What was the ratio of the number of females with caps to the number of females without caps?

b. Midway, 800 females left the carnival. In the end, there were 3/7 as many females as males remaining behind. How many people were at the carnival at first?

Hi

You may use MD or work using units.

Male ------- 14 units
Female ------ 10 units

The number of males with caps to the number of female with caps was 6:2.

Male (caps) ------- 6 units
Female (caps) ------- 2 units

Male (w/o caps) ------- 8 units
Female (w/o caps) ------- 8 units

Ratio of the number of females with caps to the number of females without caps --------- 2:8 --------1:4

The number of males remained the same.

Male -------- 14 units
Female ------- 6 units

4 units -------- 800
1 unit -------- 200

Number of people at the carnival at first ------- 24 units -------- 4800

Best wishes