Tutor MathsGuru: Ask me for your burning Maths questions!

[Dharma]

YLH88:

[quote]
Vanilla Cake wrote :
Hi YLH88,
Thanks for your highlight. You are right and you can take 21+35 which is easier to explain at P6 level. As highlighted by Dharma, pls add the number of pages read by Samir for the first 5 days (5x7=35) and add on the pages read for the next 28 days(28x7=196). So, total pages read by Samir should be 35+196=231 by then (5+28=33 days).

Thanks to Dharma for correcting my workings.

Hi Vanilla Cake, Dharma,

Sorry, I have 1 more question regarding the question above.
35 is the no of pages Dion has to read to catch but
21 is the no of pages Dion has read ahead of Samir,
why do we take 35 + 21 ?

Sorry, still abit blur on this question :?[/quote]Hi YLH88,

Here is another approach. See if you can understand.

Let us just try to find out the number of days taken Dion takes to read the same number of pages as Samir.

We try to convert this rate qns to speed qns which we may be more familiar with

When Dion starts to read, Samir had already read 35 pages (5days x 7 pages/day).

No. of days taken by Dion to catch up the no. of pages read by Samir
= 35 pages/ (9pages/day – 7 pages/day)
= 17.5 days

No. of days taken by Dion to read 21 more pages than Samir = 17.5 days + (21days/2 pages/day) = 28 days.

No. of days taken by Samir = 5 days + 28 days = 33 days.
No. of pages read by Samir = 33 days x 7 pages/day = 231 pages

[Almighty]

Hi,


Can anyone help to solve the following problems?

1)Bob and Tina started in opposite directions.Bob drove at 75 Km/h for 4 hours and found that they were 564 km apart.What was the average speed of Tina?
Ans:66Km/h

2)Mr.Lee had 36 more guppies than angelfish.He sold 1/4 of the guppies and 1/5 of the anglefish. He found that he had sold 28 more guppies than anglefish.(Model or algebra method please)
a)How many guppies did Mr.Lee have at first?Ans:416

[CoffeeCat]

Almighty:

Hi,


Can anyone help to solve the following problems?

1)Bob and Tina started in opposite directions.Bob drove at 75 Km/h for 4 hours and found that they were 564 km apart.What was the average speed of Tina?
Ans:66Km/h

2)Mr.Lee had 36 more guppies than angelfish.He sold 1/4 of the guppies and 1/5 of the anglefish. He found that he had sold 28 more guppies than anglefish.(Model or algebra method please)
a)How many guppies did Mr.Lee have at first?Ans:416

The first question is vague but they mean started at the same point but towards different direction. Bob will travel (75*4=300 km) in 4 hours.
thus Tina would have travelled (564-300=264)km in 4 hours.
Therefore tina 's aversge speed will be 264/4 = 66km/h.

For second question. If you are drawing a model, 20 units for angelfish,, 20units + 1 piece sticking out for the 36 more guppies.
When you sold 1/5 of angelfish you sold 4units of angelfish.
When you sold 1/4 of guippies you sold 5 units of guppies and 9 guppies.
Therefore 1 unit of fish = 28-9 = 19.
Guppies at first = (19 * 20 ) + 36 = 416

[YLH88]

Hi Dharma,


Yes, I’m able to understand your explanation. Thank you!!

Hi Vanilla Cake,
Also a big thank you for your help!

Regards

[firebird]

Dear mathsguru


Good morning

Please help me on the following P6 Speed math:

A Van left Port Penang for Town Lalu at 9 a.m. A Car started its journey along the same route as the Van from starting point, two hours later. The car overtook the Van at 3 p.m. The speed of the car was 30 Km/h higher than Van. The Van took 7 hours to reach Town Lalu. Find the distance between Port Penang and Town Lalu.

The answer given was:

a) The speed of the car was 30 km/h more than the speed of the Van.
So 1hr = 30 km
4hr = 4 X 30 = 120 Km

I can understand this. Reason is 4 hours = (11am - 3 pm)


b) Distance travelled from Port Penang to Town Lalu
2 hours = 120 Km
7 hours = 120/2 X 7 = 420 Km (which is the answer given)

I really do not understand how 2 hours is linked to 120 km

Please help me as to how 2 hours is linked to 120 km.
Are there different method/steps / explaination available?

Thank you
Firebird

[Dharma]

firebird:

Dear mathsguru


Good morning

Please help me on the following P6 Speed math:

A Van left Port Penang for Town Lalu at 9 a.m. A Car started its journey along the same route as the Van from starting point, two hours later. The car overtook the Van at 3 p.m. The speed of the car was 30 Km/h higher than Van. The Van took 7 hours to reach Town Lalu. Find the distance between Port Penang and Town Lalu.

The answer given was:

a) The speed of the car was 30 km/h more than the speed of the Van.
So 1hr = 30 km
4hr = 4 X 30 = 120 Km

I can understand this. Reason is 4 hours = (11am - 3 pm)


b) Distance travelled from Port Penang to Town Lalu
2 hours = 120 Km
7 hours = 120/2 X 7 = 420 Km (which is the answer given)

I really do not understand how 2 hours is linked to 120 km

Please help me as to how 2 hours is linked to 120 km.
Are there different method/steps / explaination available?

Thank you
Firebird

For fixed distance (from Port Penang to the point where car overtakes van);

Time ratio => Van: Car = 3:2 (van takes 6 hrs and car takes 4 hrs)
Speed ratio => Van: Car = 2:3

3u – 2u = 30
Speed of van = 60km/h

Distance between Port Penang & Town Lalu = 60km/h x 7hrs = 420km

[firebird]

Dear Dharma


I fully understand now.

Thank you very much.

With best regard
Firebird

[Almighty]

Thankyou very much coffee cat…I also had the same querry for the speed problem…I will assume in the same way as gn by you.Thankyou very much again.

[MOE Hater]

Hiya folks,


Went APMOPS a while back and this was one of the questions. i think the answer is 15 but if u guys get something higher, i would be happy to know. Here's the question:

what is the largest possible remainder when a 2-digit number was divided by it's digit sum?

Note: the digit sum can be a 2-digit number, it does not have to be a 1-digit number. For example, the digit sum of 99 is 18, you do not have to find the digit sum till it is a single digit number(i.e.9).

Thanks in advance :?:

[abc_parent]

Will anyone have the exam paper and help me to answer Q13b, Q14, Q15? These are questions to do with Circles and I really cannot solve. But I cannot upload pic. Will try to figure out when I really have the time!!!


But if you don’t have, can help me with this question?
Container A contains 250 red marbles and 200 blue marbles.
Container B contains 600 red marbles and 150 blue marbles.
How many red and blue marbles must be moved form Container A to Container B such that 25% of the marbles in Container A are red and 75% of the marbles in Container B are red?

Ans: 350 - Can explain step by step? Thanks!