Another Solution
Draw a rectangle FC by n with FC vertical and n horizontal. Draw a straight line from left top corner to a any point on the opposite vertical side (not a corner). Draw a vertical line anywhere in the middle and label it accordingly.
Solve for Dm by ratio and proportion, and with Dm known, BV can be found. For (a) m = 10, and for (b) m = 15.
First Cost

Salvage value

Total Depreciation

Economic life

Depreciation charge (Annual depreciation)

Appraisal values in 10 years
answer
Appraisal values in 15 years
answer
Another Solution
Draw a rectangle FC by n with FC vertical and n horizontal. Draw a straight line from left top corner to a any point on the opposite vertical side (not a corner). Draw a vertical line anywhere in the middle and label it accordingly.
Solve for Dm by ratio and proportion, and with Dm known, BV can be found. For (a) m = 10, and for (b) m = 15.