Given log 2 = 0.69, log3 = 1, 10 and log7 = 1.90, all to a fixed base, find log 10.5 to the same base without using tables.
- 1.03
-
2.31
- 3.69
- 10.5
- 25
The correct answer is: B
Explanation
log 10.5 = log \(\frac{21}{2}\)= log 21 - log 2
= log(3 x 7) - log 2
= log 3 + log 7 - log 2
= 1.10 + 1.90 - 0.69
= 3 - 0.69
= 2.31