Two planes travel toward each other from cities that are about 450 km apart at rates of 240km/r and 210km/re They started at the same time. In how many hours will they meet? The two planes will meet after square hours. (Simplify your answer.)

To find out when the will meet, we need to calculate the time it takes for them to cover the total distance between the cities.<br /><br />Let's denote the time it takes for the two planes to meet as $t$ hours.<br /><br />The distance covered by the first plane in $t$ hours is $240km/h \times t$.<br /><br />The distance covered by the second plane in $t$ hours is $210km/h \times t$.<br /><br />Since the two planes are traveling towards each other, the sum of the distances they cover will be equal to the total distance between the cities.<br /><br />So, we can set up the equation:<br /><br />$240km/h \times t + 210km/h \times t = 450km$<br /><br />Simplifying the equation:<br /><br />$450km/h \times t = 450km$<br /><br />Dividing both sides of the equation by $450km/h$:<br /><br />$t = 1$<br /><br />Therefore, the two planes will meet after 1 hour.