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.
A
1.03
B
2.31
C
3.69
D
10.5
E
25
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
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
Source: Myschool Past Questions Archive (Record #32636)