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

[Case Based Class 10] At what time will she touch the water in the - CBSE Class 10 Sample Paper for 2022 Boards - Maths Standard [MCQ]

part 2 - Question 42 (Case Based Question) - CBSE Class 10 Sample Paper for 2022 Boards - Maths Standard [MCQ] - Solutions of Sample Papers for Class 10 Boards - Class 10

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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 14 years. He provides courses for Maths, Science and Computer Science at Teachoo