20 total
6 have average of 5 years
6 x 5 = 30
20-6 = 14
14 have average of 8 years
14 x 8 = 112
112 + 30 = 142
142 / 20 = 7.1 years
Answer:
the answer to the first one would be: 4/3
the second problem's answer: 20/36, which can be reduced to 5/9
Answer:
Raul's errors are in the application of the distributive property(he applied it wrongly), in not respecting the precedence of operations, and in the multiplication of two terms with the same base(we add the exponent).
Step-by-step explanation:
Distributive property:
The distributive property of multiplication is:
a*(b + c) = a*b + a*c
Precedence of operations:
First multiplication, then addition.
Multiplication of terms with the same base:
The multiplication of h*h = h², which Raul missed.
The correct simplification is given by:
![-[3h + 7h(2-h)] = -[3h + 14h - 7h^2] = -[17h - 7h^2]=7h^2 - 17h](https://tex.z-dn.net/?f=-%5B3h%20%2B%207h%282-h%29%5D%20%3D%20-%5B3h%20%2B%2014h%20-%207h%5E2%5D%20%3D%20-%5B17h%20-%207h%5E2%5D%3D7h%5E2%20-%2017h)
Time
1 2 3 4 5
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5 10 15 20 25
Amount of water