Let 0 ≤ a ≤ x ≤ 100 and f(x) = |x - a| + |x - 100| + |x - a - 50|. Then the maximum value of f(x) becomes 100 when a is equal to
Explanation:
Since a ≤ x ≤ 100 ⇒ f(x) = x - a + -(x – 100) + |x - a - 50| ⇒ f(x) = x - a - x + 100 + |x - a - 50| ⇒ f(x) = 100 – a + |x - a - 50| ≤ 100
Option (a): a = 0 ⇒ f(x) = 100 – 0 + |x - 0 - 50| ⇒ f(x) = 100 + |x - 50| Here, when x = 0, f(x) > 100. ∴ This option is rejected.
Option (b): a = 25 ⇒ f(x) = 100 – 25 + |x - 25 - 50| ⇒ f(x) = 75 + |x - 75| Here, when x = 25, f(x) > 100. ∴ This option is rejected.
Option (c): a = 50 ⇒ f(x) = 100 – 50 + |x - 50 - 50| ⇒ f(x) = 50 + |x - 100| For any value of x ≥ 50, f(x) ≤ 100. ∴ This option is correct.
Option (d): a = 100 ⇒ f(x) = 100 – 100 + |x - 100 - 50| ⇒ f(x) = |x - 150| The only value x can take in this case is 100. ⇒ f(x) = 50 Here, the maximum value of f(x) is not 100. ∴ This option is rejected.
Hence, option (c).
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