Why not convert to decimal? Otherwise the easiest thing to do would be to multiply everything by .
Ok here is Q#1
A tank can be filled by one of two pipes in 12.00 h and by the other of the two in 1.00 h. The same tank can be emptied by a drain pipe in 10.5h. If all three pipes are open, how long will it take to fill the tank.
Answer in time?
I know it's 1/12 + 1/1 - 1/10.5 = Need to find the time it takes to fill the tank.
I have no clue on subtracing a fraction with a decimal if you have to have the LCD to clear the fractions???
Please help thanks - PLEASE EXPLAIN how it's calculated.
Joanne
I look at it this way:
They are equivalent. They are NOT in lowest term, but they represent the same quantity.
Example:
To get the LCD:
Your specific example:
get a common denominator
simplify:
=
then use the calculator to get the decimal numerator & denominator, then divide.
NOTE: This is what happens in 1 hour -- not how long it is required to actually fill the tank.
.Hope that helps.
So the answer is 166/168 but you invert it correct to 168/166
which equals 1.012 hours??
Do I have this right?
And to round to the nearest quarter of an hour.
.012 X 60 minutes = .72 of a minute?
I must be wrong, does not look right. Help in solving please.
is not the final answer...
It means all the three pipes together can fill up , or 98.81% of the total capacity of the tank, which means not 100%. In other words, it takes the pipes a little bit more than 1 hour to fulfill it.
is speed, %capacity per hour, and T is time (hour). The objective is 100%, so
x T = 100% = 1
Therefore you have T =
= 1.012 (hour)
= 1 hour + (0.012 x 60) minutes
= 1 hour 0.72 minutes
= 1 hour + (0.72 x 60) seconds
= 1 hour 43 seconds