A rock climber is climbing up a 450-foot-high cliff. By 9:30 AM, the climber had reached 90 feet up the cliff, and by 11:00 AM, he had reached 210 feet up the cliff. If he climbs with a constant speed, by what time will he reach the top of the cliff?

Explanation

Constant speed is equal distance covered in equal time periods So he will cover the rest of the distance by the same time intervals as before Distance covered : 210 ft As we have the time interval from 9: 30 to 11:00 A.M we will use the distance covered in this interval only in the ratio method Distance covered in interval 9 : 30 to 11:AM 210 - 90= 120 ft Distance remaining : 450 - 210=240 So using ratio method Ft./hrs 120/1.5=240/ x Cross multiplying =120 * x=1.5 * 240 x = 3 hrs 3 hrs is the time interval between 11 and the reaching time of the climber. So, Reaching time - option =3 hrs (converting in 24 hour clock before subtraction by adding 12 to the options) Option A) =12:00+ 1 : 45 =13 45 =13 45 - 11 = 2 hrs 45 mim Option gives wrong outcomes Option B) 12 :00 + 2 14 00 hrs 14 - 11 = 3 hrs Option is giving correct outcome Option C) 12:00 + 2 :15 14 :15 - 11= 3 hrs 15 min Option gives wrong outcomes Option D) 12:00 +2:30 =14:30 14 : 30 - 11 = 3 hrs 30 mins Option gives wrong outcomes