The kettle in Keith’s kitchen is 80% full. After 20% of the water in it has been poured out, there are 1152ml of water left.
What volume of water does Keith’s kitchen kettle hold when it is full?
3 answers
When the kettle is full, it holds 1800ml of water.
80% = 80 / 100 = 0.8
20% = 20 / 100 = 0.2
When 20% of water is poured out of it, 0.8 • 0.2 = 0.16 volume will be poured.
New volume of water will be:
0.8 V - 0.16 V = 0.64 V
Or:
100% - 20% = 80%
New volume of water will be
80% of 80% volume = 0.8 • 0.8 V =
= 0.64 V
This means:
0.64 V = 1152
V = 1152 / 0.64 = 1800 mL
20% = 20 / 100 = 0.2
When 20% of water is poured out of it, 0.8 • 0.2 = 0.16 volume will be poured.
New volume of water will be:
0.8 V - 0.16 V = 0.64 V
Or:
100% - 20% = 80%
New volume of water will be
80% of 80% volume = 0.8 • 0.8 V =
= 0.64 V
This means:
0.64 V = 1152
V = 1152 / 0.64 = 1800 mL
volume of kettle ---- x ml
amount of water in kettle at start = .8x
after 20% of that was removed, amount left = (.8)(.8x) = .64x
.64x = 1152
x = 1152/.64 = 1800 ml
amount of water in kettle at start = .8x
after 20% of that was removed, amount left = (.8)(.8x) = .64x
.64x = 1152
x = 1152/.64 = 1800 ml