Answer:
Step-by-step explanation:
Let the number be x
Five divided by the difference of the number and 8 means
5 / (x-8) and this is
equals the quotient of 10 and the sum of a number and 7.This means
10 / (7+x)
Therefore,
5 / (x-8) = 10 / (7+x)
Cross multiplying,
5(7+x) = 10(x-8)
35 + 5x = 10x - 80
5x - 10x = -80- 35
-5x = - 115
x = -115/5 = 23
2)
If Jon can paint the fence in 3 hours
This means Jon can paint the fence in 1/3 per hour
If Karen can paint it in 5 hours
This means Karen can paint the fence in 1/5 hours
Their combined rate is additive since they work simultaneously. Jon doesn't stop for Karen to work and Karen doesn't stop for Jon to work.
Their combined rate is
1/3 + 1/5 = 8/15
Let's assume the combined time is t hours.
The combined time per hour is 1/t per hour. Therefore 1/t = 8/15
t = 15/8 = 1.875 hours
