Answer:
$7.50
Explanation:
You can use proportions to find that 8/10 = 6/x
then you can multiply 10 by 6 and divide the result by 8 to get the answer.
You can also divide 10 by 8 to get 1.25 and multiply it by 6, as 10 divided by 8 gives you the unit rate, or the price of each battery. Then you multiply it by 6 to get 7.5, or the cost of 6 batteries.
Hope this helps!