Respuesta :

Answer:

$29,400

Step-by-step explanation:

21 years divided by 7 years = 3, which means we can separate this into 3 categories

$600 for 7 years is 4200

$1200 for 7 years is 8400

$2400 for 7 years is 16800

add the answers together

4200 + 8400 + 16800 = 29400