CMA Study Group

So below is the question:
Maylar Corporation has sold $50 million of $1,000 par value, 12% coupon bonds. The bonds were sold at a discount and the corporation received $985 per bond. If the corporate tax rate is 40%, the after-tax cost of these bonds for the first year (rounded to the nearest hundredth percent) is:

How i solved it was by YTM method:
((120+1000)/985)-1= 13.71%*(1-t) = 8.226%

How Hock has solved it is:

120/985=12.18*(1-t) = 7.31%

No i am super confused how to differentiate what to calculate when. I have seen other posts asking questions on similar lines.

really looking forward to a clarification

So below is the question:
Maylar Corporation has sold $50 million of $1,000 par value, 12% coupon bonds. The bonds were sold at a discount and the corporation received $985 per bond. If the corporate tax rate is 40%, the after-tax cost of these bonds for the first year (rounded to the nearest hundredth percent) is:

How i solved it was by YTM method:
((120+1000)/985)-1= 13.71%*(1-t) = 8.226%

How Hock has solved it is:

120/985=12.18*(1-t) = 7.31%

No i am super confused how to differentiate what to calculate when. I have seen other posts asking questions on similar lines.

really looking forward to a clarification

So below is the question:
Maylar Corporation has sold $50 million of $1,000 par value, 12% coupon bonds. The bonds were sold at a discount and the corporation received $985 per bond. If the corporate tax rate is 40%, the after-tax cost of these bonds for the first year (rounded to the nearest hundredth percent) is:

How i solved it was by YTM method:
((120+1000)/985)-1= 13.71%*(1-t) = 8.226%

How Hock has solved it is:

120/985=12.18*(1-t) = 7.31%

No i am super confused how to differentiate what to calculate when. I have seen other posts asking questions on similar lines.

really looking forward to a clarification