Question 1040717
A collection of stamps consist of 3¢ stamps, 7¢ stamps, and 12 ¢ stamps.
The number of 3 ¢ stamps is five less than the number of 7 ¢ stamps.
t = s - 7
----------------
The number of 12 ¢ stamps is one-half the number of 7 ¢ stamps.
w = (1/2)s
---------------------------
The total value of all the stamps is $2.73. 
t + s + w = 273
Find the number of each type of stamp in the collection. 
--------------------
Substitute for "t" and for "w" and solve for "s"::
s-7 + s + (1/2)s = 273
----------------------------
(5/2)s = 280
s = 2*56
s = 112
----
t = s-7 = 105
----
w + s/2 = 56
-----------------
Cheers,
Stan H.
-----------