Answer:
Rs 85
Step-by-step explanation:
Cost of 5kgs of rice = Rs 425
Cost of 1 kg of rice = 425/5
= Rs 85
So, the cost of a kg of rice is Rs 85
He sold 17 t-shirts. Subtract 40 from 125 and then divide 5 into 85. Your answer is 17.
Looks like you just evaluated the summand for the given value of

, whereas the question is asking you to find the value of the sum for the first

terms.
Let

. Then

is the

th partial sum.

happens to be the first term in the series, which is why that box is marked correct:

But the next partial sum is not correct:

and this is not the same notion as the second term (which indeed is 0.75) in the series.
15.26 mm. All you gotta do is convert the millimeters to centimeters, and that subtract. Make sure the decimal point is right, tho. :)