Question
a framer divides his herd of cows anong his 4 sons, one get 1/2, second get 1/4, 3rd gets 1/5 and the 4th get 7. how many cows are in the herd?
Answers
Reiny
x/2 + x/4 + x/5 + 7 = x
multiply each term by 20 and solve, it's easy from there.
multiply each term by 20 and solve, it's easy from there.
lily
thank you for your help.i got 26 as the answer. i am not sure if this is correct. i am only in the 7th grade and this is the first time i am doing this kind of problem. could you please explain a little more.
Reiny
ok, let's do it without algebra
so far he has given away 1/2, 1/4 and 1/5 of the herd
1/2 + 1/4 + 1/5
= 10/20 + 5/20 + 4/20
= 19/20 of the herd, leaving 1/20
but it said the 4th son get 7 cows, so he must have received 1/20
then if 1/20 equals 7 then
20/20 , or the whole herd, must have been 20x7 or 140 cows
check:
1/2 of 140 = 70
1/4 of 140 = 35
1/5 of 140 = 28
sum of 70+35+28+7 = 140
so far he has given away 1/2, 1/4 and 1/5 of the herd
1/2 + 1/4 + 1/5
= 10/20 + 5/20 + 4/20
= 19/20 of the herd, leaving 1/20
but it said the 4th son get 7 cows, so he must have received 1/20
then if 1/20 equals 7 then
20/20 , or the whole herd, must have been 20x7 or 140 cows
check:
1/2 of 140 = 70
1/4 of 140 = 35
1/5 of 140 = 28
sum of 70+35+28+7 = 140
lily
oooooooooooooooo that makes alot more sense, thank you!