Q&A - P5 Math

[BigDevil]

[angel]

There were 381 people in a school hall. When 3/4 of the boys and 7/9 of the girls left the school hall, the total number of pupils who remained became 93. How many boys and how many girls left the school hall?

[zeemimi]

There were 381 people in a school hall. When 3/4 of the boys and 7/9 of the girls left the school hall, the total number of pupils who remained became 93. How many boys and how many girls left the school hall?

B+G+G=93
4 x (B+G+G)=93x4 = 372
1G=381-382 = 9
7G = 9x7 = 63

B+G+G=93
B+9+9=93
B=93-18 = 75
3B=75x3 = 225

63 girls and 225 boys left the school hall.

[angel]

There were 120 people at a party. 25% of women and 2/3 of men left the party. There were 60 people left at the party. How many women were there at the party?
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Can I take 25% as 1 unit?

[Ender]

There were 120 people at a party. 25% of women and 2/3 of men left the party. There were 60 people left at the party. How many women were there at the party?
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Can I take 25% as 1 unit?

That's one idea .
From the questions, we get the idea that women can be divided by 4 units, and the men can be divided by 3 units.

Hence I would let women be 4W, and men be 3M.

4W + 3M = 120
3W + 1M = 60

Find W and you will be able to find the number of women at the party at first, which is 4W.

[angel]

There were 120 people at a party. 25% of women and 2/3 of men left the party. There were 60 people left at the party. How many women were there at the party?
-----------------------------------------
Can I take 25% as 1 unit?

That's one idea .
From the questions, we get the idea that women can be divided by 4 units, and the men can be divided by 3 units.

Hence I would let women be 4W, and men be 3M.

4W + 3M = 120
3W + 1M = 60

Find W and you will be able to find the number of women at the party at first, which is 4W.

IS the answer 48?

[Ender]

The question wasn't clear as to whether it want the number of women at the party at first or in the end. Assumming it's at first, yes, 48 is the answer

[angel]

The question wasn't clear as to whether it want the number of women at the party at first or in the end. Assumming it's at first, yes, 48 is the answer

yes, at first. Sorry. I didnt type correctly. Thank you Ender. You are bringing back some confidence in me. Thank you.

[angel]

How about this one?

Jon has 1120 apples and oranges. 20% of apples and 5% of oranges make up 146 of the fruits. How many apples are there?

is Orange = 20 units?

[angel]

another question.

A and B had $10400. A spent 3/4 of her money and B spent 3/5 of his money. B now has $520 more than A. How much money did each of them have first?

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one equation is a plus, the other is an subtraction. How to compare the 2 equations?