Q&A - P5 Math

[dazzlego]

heyhoe:

Hi,


I need help with this maths question:-
The Lim family of two adults and three children are 100 years old altogether. The sum of the father's age and the son's age is 51 years in total. The father is 3 years older than the mother. While the twin daughters are each 5 years younger than the brother. Can you work out everyone's age?

You can use this assumption using units and parts then work it out

Father's age = 1 unit
Mother's age = 1 unit - 3
Son's age = 1 part
Daughter's age = 1 part - 5

Father + Son :
1 unit + 1 part = 51

Mother + 2 Daughter :
(1 unit - 3) + (1 part - 5) + (1 part - 5) = 49
1 unit + 2 parts - 13 = 49
1 unit + 2 parts = 62

From those 2 equations,
1 part = 62 - 51 = 11 (Son)
11 - 5 = 6 (Twin Daughters)
51 - 11 = 40 (Father)
40 - 3 = 37 (Mother)

Hope it helps,
Cheers :celebrate:

[speedmaths.012624com]

ttyh:

What is the sum of all the odd numbers that are less than 100?

(Surely there is some sort of formula for this??)
Pls help! Thanks

Hi,

The solution below is copied from the book:
\"Go For A* - Volume 1A\"
published by Amazing Books.

Hope it helps.

Cheers


speedmaths.com


=

1 + 3 + 5 + ... + 99

1) First, find the Average of all these numbers:
Average = (First Number + Last Number) / 2
Average = (1 + 99) / 2 = 50

2) Next, find the Number of Terms (or how many numbers are there):
For a series of odd numbers starting with 1,
the Average is also equal to the Number of Terms
Number of Terms = 50

3) Sum = Average x Number of Terms
Sum = 50 x 50 = 2500


.

[heyhoe]

Hi dazzlego,


Thank you so much for the clear explanation.

dazzlego:

heyhoe:

Hi,

I need help with this maths question:-
The Lim family of two adults and three children are 100 years old altogether. The sum of the father's age and the son's age is 51 years in total. The father is 3 years older than the mother. While the twin daughters are each 5 years younger than the brother. Can you work out everyone's age?

You can use this assumption using units and parts then work it out

Father's age = 1 unit
Mother's age = 1 unit - 3
Son's age = 1 part
Daughter's age = 1 part - 5

Father + Son :
1 unit + 1 part = 51

Mother + 2 Daughter :
(1 unit - 3) + (1 part - 5) + (1 part - 5) = 49
1 unit + 2 parts - 13 = 49
1 unit + 2 parts = 62

From those 2 equations,
1 part = 62 - 51 = 11 (Son)
11 - 5 = 6 (Twin Daughters)
51 - 11 = 40 (Father)
40 - 3 = 37 (Mother)

Hope it helps,
Cheers :celebrate:

[Jamesbond]

MathIzzzFun:

Jamesbond:

Dawn and Minny had the same number of stickers at first. After Dawn gave 24 stickers to Minny. Minny had 5 times as many stickers as Dawn. How many stickers did Minny have at first?


Is some info missing in this sum....or is it possible to solve....My ds doubt....Pl help..

Hi

you can use MD or ratio ..
...concept --> total number of stickers remain the same...

In the end
Dawn's stickers : Minny's stickers --> 1u : 5u (total 6u)

at first
Dawn's stickers : Minny's stickers = 1:1 --> 3u : 3u (total 6u)

From above, observe that Dawn gave away 2u, and Minny received 2u

So, 2u --> 24, 1u--> 12
At first, Minny's stickers --> 3 x 12 = 36

cheers.

Ratio not yet started for my ds...can u explain in a diff way? Thx.

[MathIzzzFun]

Jamesbond:

MathIzzzFun:

[quote=\"Jamesbond\"]Dawn and Minny had the same number of stickers at first. After Dawn gave 24 stickers to Minny. Minny had 5 times as many stickers as Dawn. How many stickers did Minny have at first?


Is some info missing in this sum....or is it possible to solve....My ds doubt....Pl help..

Hi

you can use MD or ratio ..
...concept --> total number of stickers remain the same...

In the end
Dawn's stickers : Minny's stickers --> 1u : 5u (total 6u)

at first
Dawn's stickers : Minny's stickers = 1:1 --> 3u : 3u (total 6u)

From above, observe that Dawn gave away 2u, and Minny received 2u

So, 2u --> 24, 1u--> 12
At first, Minny's stickers --> 3 x 12 = 36

cheers.

Ratio not yet started for my ds...can u explain in a diff way? Thx.[/quote]If A has same number of marbles as B, when A give 1 marble to B, B will have 2 more than A - A lose 1, B gain 1 so difference of 2.


similarly, after Dawn gave 24 to Minny, Minny will have 48 more than Dawn
so, 4 units --> 48, 1 unit --> 12 (Dawn, in the end )

At first, Minny's stickers = Dawn's stickers = 12 + 24 = 36

cheers

[tayobus]

:?: :salute: :thankyou:


An equal number of male & female runners participated in a marathon race.
After 980 female runners and 350 male runners dropped out of the race, the number of female runners left was 1/6 the number of male runners.
What was the total number of runners at the start of the race?
(Can help by showing the model-drawing?)

[MathIzzzFun]

tayobus:

:?: :salute: :thankyou:


An equal number of male & female runners participated in a marathon race.
After 980 female runners and 350 male runners dropped out of the race, the number of female runners left was 1/6 the number of male runners.
What was the total number of runners at the start of the race?
(Can help by showing the model-drawing?)

Hope this comes out ok... sketch on mobile...

http://i48.tinypic.com/16h3xo7.jpg\">

cheers.

[chloecube]

jack wants to buy a bicycle but is short of $44. Jill wants to buy the same bicycle but is short of $37. if they combine their money, they will have just enough money to buy the bicycle. what is the cost of 2 such bicycle?


thks for helping

[chloecube]

i think of a number which is less than 50. when the number is divided by 7. the reminder is 1. when the number is divided by 12, the reminder is 7. what is the number?


other than guessing, is there an easier method?

[chloecube]

what is the value of 1-2+3-4+5…47-48-49?

is the a formula for such question?

sorry for so many questions,thks