High School

The average weight of six people sitting in a boat is 145 pounds. After a seventh person gets into the boat, the average weight of all seven people in the boat is 147 pounds.

What is the weight (in pounds) of the seventh person?

A. 160
B. 159
C. 155
D. 149
E. 147

Answer :

Weight :

⇒ x for 6 people
⇒ y for the 7th person

[tex]x/6=145 \\ (x+y)/6=147 \\ \\ x=145*6 \\ x=870 \\ \\ x+y=1029 \\ \\ 870+y=1029 \\ y=1029-870 \\ y=159[/tex]

The correct answer is B).
x - weight of six people
y - weight of 7th person

[tex]\frac{x}{6}=145\\
\frac{x+y}{7}=147\\\\
x=870\\
x+y=1029\\\\
870+y=1029\\
y=159\ lb\Rightarrow B[/tex]

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