Question

A line of true length 500 m when measured by a 20 m tape is reported to be 502 m long. The correct length of the tape is

A. 19.92 m B. 20.08 m C. 20.80 m D. 21 m

Answer 1

While measuring the length with 20m tape, we made 500 m / 20 m = 25 spans of measurements.  I mean we used the full lenght of tape 25 times to completely measure the true length.

Now let the actual or correct length of tape be X meters
25 * X = 502 meters          => X = 502/25 = 20.08 m

Answer is B

Answer 2

Ans) spans of measurement=500/20 =25
It means that the full length of tape of 20 m was used 25 times to measure a line 500 m.

So, let the actual length of the tape be X

So, 25x=502
x=20.8 m

Option B is correct