Frank can build a fence in twice the time it would take Sandy. Working together, they can build it in 7 hours. How long will it take each of them to do it alone?
Answer
If Frank and Sandy can build the fence in 7 hours, they must be building
1
7
of the fence every hour.
Now, let the amount of time it takes Sandy be
x
hours so that Frank takes
2
x
hours. Sandy can build
1
x
of the fence every hour and Frank can build
1
2
x
of the fence every hour.
We now have the following equation to solve.
1
x
+
1
2
x
=
1
7
2
+
1
2
x
=
1
7
21
=
2
x
x
=
21
2
=
10.50
Thus, Sandy takes
10.50
hours and Frank takes
21
hours.
I am in my kitchen if and only if i am at home
not 100% right
Answer:
20
Step-by-step explanation:
A=20
Answer:
Brand X has to mix 8.4 oz of brand A mixed nuts which contain 35% peanuts and 12.6 oz of brand B mixed nuts which contain 25%, to obtain 21 oz. Bags of mixed nuts that contain 29% peanuts.
Step-by-step explanation:
Hi
We define
, wich means Brand A has 1 oz containing 35% peanuts.
, wich means Brand b has 1 oz containing 25% peanuts.
So we can build an equiation system
(1) 
(2)
, after fixing it a little
(2)
As we can use any method to solve the system, I used a calculator wich thrown the following results 
and 
.
