If the cost of 20 stamps is $9.80, how
much will 1 stamp cost?

1 stamp will cost $0.49.

Step-by-step explanation:

20/9.8=1/x

cross product

20*x=9.8*1

20x=9.8

x=9.8/20

addition

step-by-step explanation:

yes, gavin is right.

step-by-step explanation:

gavin is correct. 

this problem is about converting 9% per year to how many percent per quarter. the rate is still the same. it only differed in the time period. so, through dimensional analysis,

9% per year  × (1 year / 4 quarters) = 2.25% per quarter

if he was asked to convert 9% per year to how many percent per quarter  compounded quarterly, then you will not simply divide by four. this is because compounding is not linear.

hope this , have a good day. c;