MATH Q: how long will it take to reduce the charge to 25% of its original charge?

Question

A storage battery discharges at a rate which is proportional to the charge. If the charge is reduced by 50% of its original value at the end of 2 days, how long will it take to reduce the charge to 25% of its original charge? (with solution)

Answer 1

Sounds like a simple half-life problem.
Battery discharges half of it's charge in 2 days.
After 2 days, it has 50%. 50% of 50% is 25%, so it will take 2 more days.

Math would use a an exponential equation along a hyperbolic curve.

Answer 2

ok if it takes 2 days to reduce it to 50% of it's original charge then it would take 3 days to reduce it to 25% of its original charge.
This is a basic math question using proportions. For each 25% it will take 1 day.

Answer 3

i think is 4 days. because if you reduce the 50% of the charge in 2 days and the rate is proportional. that says that the half of the charge is discharge in 2 days. and if you have now 50% of the charge and you discharge again the battery, that says that the half of the battery (50%) will discharge in 2 more days... hope im right...

Answer 4

3 days from full to 25 and 1 day from 50 to 25

Answer 5

it will take 2 more days. Lets say we have 20V in the battery. we reduce it by 50% so that it is now 10. it took us 2 days to do this so the rate is 5V per day. the charge is now reduced by 50% so the rate will go down by 50% so 5V per day becomes 2.5V per day. 25% of 20 is 5 so we need 2 days to reduce the charge at the current rate.

Answer 6

4 days

Answer 7

it will take 1 day
48hr=50%
25%
cross multipliction

Answer 8

IT WILL TAKE 4 DAYS.