E= hf-w
w= ?

options
a) e/hf
b) -e/hf
c) e+hf
d) hf-e

choose the right option from above.

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is