A pre-paid calling card costs $10. If purchased, it will allow the user to make calls for 5.2 cents per minute until the $10 amount is used. How do you calculate the number of minutes, rounded to the nearest minute, of this calling card?

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Answer 1 · 2017-03-22T14:35:23

#1000 div 5.2 = 192.3#

You have #192# minutes on this call card.

In word problems like these, the first decision is which operation to do? #" "+ - xx div?#

You could think of this as a subtraction of #5.2#c for every minute.

Keep subtracting #5.2c# until you get to 0. The number of subtractions is the number of minutes you can use.

#$10 = 1,000c#

#1,000 -5.2-5.2-5.2" " ....... -5.2 = 0#

However, division is the short cut for repeated division.

#1000 div 5.2 = 192.3#

You have #192# minutes on this call card.

Answer 2 · 2017-03-22T15:03:35

#192# minutes (to the nearest minute)

#5.2cents=1 #minute

#:.$10=1000# cents

#:.1000=1000/5.2=192.3076923# minutes

#:.=192# minutes (to the nearest minute))