An advertising agency conducted a survey and found that the number of units sold, N, is related to the amount a spent on advertising (in dollars) by the following formula:

Question

An advertising agency conducted a survey and found that the number of units sold, N, is related to the amount a spent on advertising (in dollars) by the following formula: 
N = 6,500 + 400 ln a    (a ≥ 1)
How many units are sold after spending $1,000? (Round your answer to the nearest whole number.)

VICTOR · Answer

you have the formula. Plug in 1000 for N and evaluate.