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    Question

    The speed of a bike increases by 2 km/hr after every 1

    hour. If the distance travelled by the bike in 1st hour is 35 km, the find the total distance travelled by the bike in 16 hours.
    A 800 km Correct Answer Incorrect Answer
    B 500 km Correct Answer Incorrect Answer
    C 850 km Correct Answer Incorrect Answer
    D 750 km Correct Answer Incorrect Answer

    Solution

    Since, the speed of the bike increases by 2 km/hr after every 1 hour, therefore the bike will travel 2 km extra after every 1 hour. Therefore, distance travelled by the bike in 1st hour = 35 km Distance travelled by the bike in 2nd hour = 35 + 2 = 37 km Distance travelled by the bike in 3rd hour = 37 + 2 = 39 km This form an AP i.e. 35, 37, 39………distance travelled in 10th hour Therefore, total distance travelled by the bike in 16 hours = sum of the AP Distance travelled in 16 hours = (n/2){2a + (n – 1)d} Where n = number of terms = 16, a = 1st term = 35 and d = common difference = 2 Therefore, distance travelled in 16 hours = (16/2){2 × 35 + (16 – 1) × 2} = (16/2)(70 + 30) = 800 km

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