Lina purchased a prepaid phone card for $15. Long distance calls cost 16 cents a minute using this card. Linda used her card only once to make a long distance call. If the remaining redit on her card if $10.52, how many minutes did her call last?

Lina spent 28 minutes on the call.

Explanation:

let n be the number of minutes lina made a call

then:

cost of long distance call is 16 cents/min = 0.16 dollars/min

number of dollars spent on the long distance call = 0.16n

if the total dollars of the phone card is $15 and the remaining dollars after the call is $10.52, this implies that:

$15 = $10.52 + (0.16n) $

n = (15 - 10.52) / 0.16

= 28

Therefore, lina spent 28 minutes on the call.