Question 1158821
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(1) In the 1.5 hours that the first plane flew before the second took off, the first plane traveled 1.5(520) = 780km.<br>
(2) The second plane catches up to the first at the rate of (580-520)=60km/hr.<br>
(3) The number of hours the second plane takes to make up the 780km is 780/60 = 13.<br>
ANSWER: 13 hours<br>