Goodwill is the reputation of a business earned over some years represented in monetary terms. Whenever there is a change in the constitution of a partnership by way of admission,retirement or death, a valuation of goodwill is necessary.
In the given question we have to calculate hidden goodwill. Hidden goodwill is the goodwill which is not given in the question and we have to calculate it on the basis of total capital of the firm and other given information.
C's share is 1/4th and he brings 70,000 as his capital.
Total capital = 70,000 * 4 = 2,80,000
3/4th capital = 2,80,000-70,000 = 2,10,000
Total capital of A and B = 1,20,000+1,20,000 = 2,40,000
Value of goodwill = Difference between old and new capital
= 2,40,000 - 2,10,000 = 30,000
For 1/4th share, C is bringing 70,000 as capital. So,the new capital of the firm on the basis of C's capital is 2,80,000. A and B capital according to their ratio i.e 1:1 should be 2,10,000/2 = 1,05,000 each. So,the excess is goodwill.