<span>(x-2/3)+(1/60)=(5/6)
x-2/3= 5/6 - 1/60
x-2/3 = 49/60
x - 2 = 49/20
x = 49/20 + 2
x = 89/20
The answer is: x = 89/20 or x = 4.45.
</span>
B is the best strategy. (You mentioned an option D, but it's not shown in your question!!)
Given nth term of an AP = 7-4n
Put n = 1 then t1 = 7-4(1) = 7-4 = 3
Put n = 2 then t2 =7-4(2) = 7-8 = -1
Common difference = t2-t1 = -1-3 = -4
