ongmt:

1) At a party, there were some ballons, 25 ballon burst & 10% of remaining ballons fly away. If only 60% of the ballons were left, how many ballons were there at first?

9 units -> 60%
1 unit -> 6 2/3%
10 units -> 66 2/3%

100% - 66 2/3% = 33 1/3%
33 1/3% -> 25 balloons
100% -> 75 balloons

There were 25 balloons at first.

ongmt:

2) Pkt A, B and C each contained some cement. 1/3 of cement was transferred from Pkt A to B. Then 1/3 of the cement transfer from Pkt B to C. Finally, 1/3 of cement transferred from Pkt C to A. In the end, there were 12kg of cement in each pkt. Whar was the mass of cement in Pkt B at first?

This is a 'constant total' or 'internal transfer' type of qn.

Working backward

At the end,
A:B:C = 12:12:12

1/3 from C to A,
2 units left in C
1 unit -> 6 kg
A:B:C = 6:12:18

1/3 from B to C,
2 units left in B
1 unit -> 6 kg
A:B:C= 6:18:12

1/3 from A to B,
2 units left in A
1 unit -> 3 kg
A:B:C=9:15:12

Pkt B had 15 kg of cement initially.

ongmt:

Jason, Edward and Sam had total $837. Jason had the least amont of money. Ratio of Edward money to Sam money was 4:3 at first. Jason and edward spent 1/3 of their money. Given that the 3 boys had $648 left, how much did Jason have at first? :?


Plse help. Thks

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Amt spent by J and E -> $837 - $648 = $189
Initial total of J and E -> $189 x 3 = $567
Initial amount of S -> $837 - $567 = $270

At first, E:S -> 4:3
3u -> $270
1u -> $90
4u -> $360

At first, J -> $567 - $360 = $207
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Cheers