Q&A - PSLE Math

[oceandeep]

[Moderator's note: Topics merged.]


Gina, Hans, Ian and June bought a present for their mother. Gina paid 2/5 of what the rest paid. Hans paid 1/2 of what the rest paid. Ian paid 1/3 of what the rest paid. June paid $30 less than Ian. how much did the present cost?

[CMF]

Gina : 2 units

The rest : 5 units
Total : 7 units

Hans : 1 unit
The rest : 2 units
Total : 3 units

Ian : 1 unit
The rest : 3 units
Total : 4 units

Hence find the lowest common multiple of 3, 4 and 7 which is 84

As such :

Gina : 24 units
Hans : 28 units
Ian : 21 units

To find June’s share : Subtract (24 + 28 + 21) from 84 which gives 11 units.

Since June paid $30 less than Ian and the difference betw them is 10 units, 10 units therefore represents $30.

From the above, the total cost is $252 as the total number of units is 84
10 units : 10 x 3 = $30
84 units : 84 x 3 = $252

[Kari]

[Moderator's note: Topics merged.]


Lily is meeting a friend at a certain time.If she drives at 80km/hr, she will be 1/3 hour late. If she drives at 60km/hr, she will be 3/4 hour late. How long will the journey take if she drives at 90 km/hr?

[Eagle-Ladybird]

Kari:

Lily is meeting a friend at a certain time.If she drives at 80km/hr, she will be 1/3 hour late. If she drives at 60km/hr, she will be 3/4 hour late. How long will the journey take if she drives at 90 km/hr?

1 hr 11 minutes

[Kari]

[Moderator's note: Topics merged.]

After 20 minutes into a cross country race, Teck Seng has run 5/8 of the route while Jack has covered only 3/8 of the distance. Teck Seng runs at the same average speed throughout the race and Jack's average speed is 60 min/min slower than Teck seng's.

a) Find the total distance of the cross country race.

b) If Jack wants to finish the race at the same time as Teck Seng, by how much should he increase his average speed for the remaining part of the race? (Express your answer in m/min)[/img]

[Eagle-Ladybird]

Is there a typo on "60min/min" above ??

[k1ndan]

[Moderator's note: Topics merged.]


1. Mrs. Tan has drawn up a schedule to have her home cleaned by 3 part-time workers. The cleaner goes to her home once every 3 days, the sweeper once every 4 days and the gardener once every 6 days. If the 3 workers first met on 28 July, when was the earliest date the cleaner has to start work?

2. Mary is meeting a friend at a certain time. If she drives at 80 km/h, she will be 1/3 hour late. If she drives at 60 km/h, she wil be 3/4 hour late. How long will the journey take if she drives at 90 km/h?

[Eagle-Ladybird]

1. 3 days after 28 july i.e. 31 july


2. 1 hr 11mins

[jedamum]

1. Do a search before starting new topic.


2. Mods, please merge with http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=280. TQ.

[Dharma]

Kari:

[Moderator's note: Topics merged.]

After 20 minutes into a cross country race, Teck Seng has run 5/8 of the route while Jack has covered only 3/8 of the distance. Teck Seng runs at the same average speed throughout the race and Jack's average speed is 60 min/min slower than Teck seng's.

a) Find the total distance of the cross country race.

b) If Jack wants to finish the race at the same time as Teck Seng, by how much should he increase his average speed for the remaining part of the race? (Express your answer in m/min)[/img]

http://www.postimage.org/