The average of three values is 50. First value is 1/2 of the third value. Third value is 30 more than second value. What is the first value?
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Correct answer: A
Explanation
Given:
Average of three values = 50
First value = 1/2 of the third value
Third value = Second value + 30
According to the formula:
Average = Sum of values / 3
Let the second value = x
Third value = x + 30
First value = (x + 30)/2
Sum of values = 50 × 3 = 150
⇒ (x+30)/2 + x + (x+30) = 150
⇒ (x+30 + 2x + 2x + 60)/2 = 150
⇒ (5x + 90)/2 = 150
⇒ 5x + 90 = 300
⇒ 5x = 210
⇒ x = 42
First value = (42 + 30)/2 = 72/2 = 36