robert bought 8 dollars worth of 6 cent stamps and 8 cent stamps. He has a total of 110 stamps. Find how many of each stamp he has.
Let x be the number of 6 cent stamps. Then 110 - x equals the number of 8 cent stamps. So we have... (in cents).....
6x + 8(110 - x) = 800 simplify
6x + 880 - 8x = 800
-2x + 880 = 800 subtract 880 from both sides
-2x = - 80 divide both sides by -2
x = 40 and that's the nimber of 6 cent stamps
And (110 - 40) =70 and that's the number of 8 cent stamps
Cphill thats an excellent answer (obviously...as always)...but as usual the problem is i dont get this step...i mena cna you tell me why you did it like this....explain....
6x + 8(110 - x) = 800 simplify
Rosala.....
Notice that the cost of each stamp type times the number of them can be written as :
6 cents x the number of 6 cent stamps + 8 cents x the number of 8 cent stamps = the total cost (8.00 or 800 cents)
Or simply
6x + 8(110 - x) = 800 [I'm expressing everything in terms of cents in this equation ]
Does that make sense ????