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Out of four numbers, the average of the ...

Out of four numbers, the average of the first three is 15 and that of the last three is 16. If the last number is 19, the first is

A

18

B

19

C

15

D

16

Text Solution

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The correct Answer is:
D
मानाकि चारों संख्या क्रमशः a, b, c, d है।
`(a+b+c)/3 = 15`
`implies a + (b + c) = 45 ...............(i) `
`(b+c+d)/(3) = 16`
`implies b + c + d = 48`
`implies b + c + 19 = 48 " " `(d = 19 दिया है)
`implies b + c = 48 - 19 = 29`
`(b+c)` का मान समी. (i) में रखने पर
`a + 29 = 45`
`implies a = 45 - 29`
`therefore a = 16`
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