If $10,000 is invested in an account at 4.8% annual simple interest, how long will it take for the account balance
to grow to $11,200?

and explain, .

10000+4.8%=10480
10480+4.8%=10983.04
10983.04+4.8%=11510.22592

so 3 years

So the equation you should make is 11200=10000+480x because you would make $480 per year and "x" equals  the numbers of years so by solving this equation X=2.5 so it takes 2.5 years to reach $11200. and disregard the previous answer. 

It is the top one. the answer is -7. that is smallest