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4-73.

The gross national product (GNP) was $1.665 · 10^{12}$ dollars in 1960 and it increased at the rate of $3.17\%$ per year until 1989. Use this information to answer each of the questions below. (The number $1.665 · 10^{12}$ is expressed in scientific notation. Written in standard notation, the number is $1,665,000,000,000$.)

1. What was the GNP in 1989?

$y = 1.665 · 10^{12}\left(1.0317\right)^{29}$

Multiply the GNP in 1960 by $1.0317$ twenty-nine times.

The GNP in 1989 is $4.116 · 10^{12}$ dollars.

1. Write an equation to represent the GNP t years after 1960, assuming that the rate of growth remained constant.

Remember that the GNP increases by $3.17\%$ each year.

$y = 1.66\left(10^{12}\right)\left(1.0317\right)^{t}$

1. Do you think the rate of growth really remains constant? Explain.

If you don’t know or you aren’t sure, try looking it up on the internet. Look for a graph. You could enter GNP USA into a search engine.