The answer is d 100 inches
Answer: 
Step-by-step explanation:
You need to use the following Properties of Logarithms:

Given the following expression:

You can follow these steps in order to write it as a single logarightm:
- Apply the first property shown above:

- Apply the second property:

- Finally, apply the third property:

Inches and centimeters are different units of measurement, one English, one metric. Converting from one to the other requires use of a conversion factor.
One such factor can be derived from 1 inch = 2.54 cm. This means that one inch is 2.54 times longer than one cm.
The lowest common multiple of 2 and 7 is 14, so 14 days will pass before he does both chores again.
Answer:
^algebra^
#1). a - b=4
a=4 + b .....(equation 1)
#2) a + b=12
(4 + b) + b= 12
4 + b + b=12
4 + 2b=12
2b= 12 - 4
2b =8
b= 8:2
b=4
subtituted b in equation 1
a= 4 + b
a= 4 + 4
a=8
so, the number is 8 and 4