Tutor MathsGuru: Ask me for your burning Maths questions!

[iFruit]

atutor2001:

What iFruit means is...

Thank you atutor2001.

[Dharma]

Hifive:

Hi everyone


Need help with this P5 question:

The total of 4 numbers was 390. When the first number was tripled, the second number halved, the third number increased by 28 and the 4th number decreased by 15, the 4 numbers became equal. Find the original value of each number.

Thanks in advance.

(3u/3) + (3u x 2) + (3u - 28 ) + (3u + 15) = 390
13u = 390 + 28 – 15 = 403
1u = 31
Original value of each number:
1st = 1u = 31
2nd = 6u = 186
3rd = 3u – 18 = 75
4th = 3u + 15 = 108

[Hifive]

Hi Dharma


Thanks for your explanation!

[Dharma]

Hifive:

Hi Vanilla Cake


Thanks for your explanation!

There is one more question:

Jenny and Lydia wanted to buy some souvenirs for their friends when they were on a holiday. They had a total amount of $625 with them. Jenny had $115 more than Lydia. At the souvenir shop, Lydia spent half of what Jenny spent. In the end, Lydia was left with 4 times as much money as Jenny. How much did Jenny spend?

Thanks again.

2u + $115 = $625
2u = $510
1u = $255

Jenny => $255 + $115 = $370
Lydia => $255

$255 – 1p = 4($370 – 2p)
$255 – 1p = $1480 – 8p
7p = $1225
1p = $175

Amt Jenny spent = 2p = 2 x $175 = $350

[atutor2001]

iFruit:

Thank you atutor2001.

You are most welcome. I like your approach to math questions.

[Hifive]

Dharma:

2u + $115 = $625...

Hi Dharma

Thanks for the solution. Can you pls explain why you place
$255 – 1p = 4($370 – 2p)

is it to \"balance\" up both sides since Lydia has 4 units left?

[powforhighschool]

Two candles of the same height are lit at the same time. the first is consumed in 4 hours and the second in 3 hours. Assuming that each candle burns at a constant rate, in how many hours after being lit was the first candle twice the height of the second?

[tianzhu]

powforhighschool:

Two candles of the same height are lit at the same time. the first is consumed in 4 hours and the second in 3 hours. Assuming that each candle burns at a constant rate, in how many hours after being lit was the first candle twice the height of the second?

Hi

If you are looking for algebra solution, here's one from vanilla cake for a similar type of question.

Candle A and candle B are of the same length. Candle A, which is broader, can burn for 5 h while Candle B, the thinner candle, can burn for 4 h. If both candles are lighted at the same time, how long does it take for Candle A to be twice as long left as Candle B?

Using algebra :

Assume the number of hours burnt be n
1 on the left side is 5/5 and 1 on the right hand side is 4/4

1-n/5=2(1-n/4)
1-n/5=2-n/2
(5-n)/5=(4-n)/2
2(5-n)=5(4-n)
10-2n=20-5n
3n=10
n= 3⅓ hours

It takes 3⅓ hours for Candle A to be twice as long left as Candle B.

Best wishes

[Dharma]

Hifive:

Hi Dharma


Thanks for the solution. Can you pls explain why you place
$255 – 1p = 4($370 – 2p)

is it to \"balance\" up both sides since Lydia has 4 units left?

Exactly... Lydia had 4 times as much money as Jenny at last.

[Hifive]

Hi Dharma


Thanks! Have a nice day!