# Question

pls help to solve the qn. thank you.

Base area of Tank A = 25 × 30 = 750 cm²

Base area of Tank B = 25 × 50 = 1250 cm²

Both taps fill the tanks at 1 500 cm³ per minute.

For Tank A, 1500 ÷ 750 = 2 cm increase in height per minute

For Tank B, 1500 ÷ 1250 = 1.2 cm increase in height per minute

2 – 1.2 = 0.8 cm per minute

Tank B is 1/4 filled. The height of the water is 1/4 × 40 = 10 cm

10 ÷ 0.8 = 12.5 minutes

It will take 12.5 minutes for the water level in the two tanks to be the same height.

0 Replies 0 Likes ✔Accepted Answer

Water in B:
50 x 25 x 40 = 50 000
4 units -> 50 000
1 unit -> 12 500

Height in B:
12 500 / (50 x 25) = 10 cm

Base area of A:
30 x 25 = 750

Base area of B:
50 x 25 = 1250

1 litre = 1000 cm cube
1.5 litre = 1500 cm cube

Every min, height increase in A:
1500 / 750 = 2 cm

Every min, height increase in B:
1500 / 1250 = 1.2 cm

Every 5 mins, height increase for A and B:
A: 2 x 5 = 10 cm
B: 1.2 x 5 = 6 cm

Every half min, height increase for A and B:
A: 2 x 0.5 = 1 cm
B: 1.2  0.5 = 0.6 cm

Height in   A,          B
0 min         0 cm    10 cm
5 mins       10 cm   16 cm
10 mins     20 cm   22cm
11 mins      22 cm   23.2 cm
12 mins     24 cm   24.4 cm
12.5 mins  25 cm   25 cm

Therefore, the timing is 12.5 mins.