Check sibling questions

At what time will she touch the water in the pool?

(a) 30 seconds   (b) 2 seconds  

(c) 1.5 seconds   (d) 0.5 seconds

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Question 42 At what time will she touch the water in the pool? (a) 30 seconds (b) 2 seconds (c) 1.5 seconds (d) 0.5 seconds Now, h(t) = −16t2 + 8t + 48 We need to find At what time will she touch the water in the pool Putting h = 0 in equation h(t) = −16t2 + 8t + 48 0 = −16t2 + 8t + 48 16t2 − 8t − 48 = 0 Dividing by 4 both sides 4t2 − 2t − 12 = 0 Solving by splitting the middle term 4t2 − 8t + 6t − 12 = 0 4t(t − 2) + 6(t − 2) = 0 (4t + 6) (t − 2) = 0 ∴ t = (−6)/4=(−𝟑)/𝟐 and t = 2 Since time cannot be negative ∴ t = 2 seconds So, the correct answer is (b) Splitting the middle term method We need to find two numbers whose Sum = −2 Product = −12 × 4 = −48

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.