What is the minimum number of days he needs to practice till his goal is achieved?

Question

Your friend Veer wants to participate in a 200 m race. He can currently run that distance in 51 seconds and with each day of practice it takes him 2 seconds less. He wants to complete the race in 31 seconds.

Based on the above information answer the following question:

(ii) What is the minimum number of days he needs to practice till his goal is achieved?

Smart Achievers · Accepted Answer

(1)

Let he has to practice for n days

$a ₙ = 31 \Rightarrow a + (n - 1) d = 31, a = 51, d = - 2 \Rightarrow 51 + (n - 1) (- 2) = 31 \Rightarrow - 2 (n - 1) = 31 - 51 = - 20 \Rightarrow n - 1 = 10 \Rightarrow n = 11$

Minimum number of days = 11

Solution

1 11

2 12

3 13

4 15

Ans.
(1)

Let he has to practice for n days

$a ₙ = 31 \Rightarrow a + (n - 1) d = 31, a = 51, d = - 2 \Rightarrow 51 + (n - 1) (- 2) = 31 \Rightarrow - 2 (n - 1) = 31 - 51 = - 20 \Rightarrow n - 1 = 10 \Rightarrow n = 11$

Minimum number of days = 11

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