difficult word problem ( in description) please need help

Question

Please send how to do it as an equation not just answers

 

Dudley has a number of 10-cent and 20-cent coins. If their total value is $6, how many are there of each coin: a) equal numbers of each coin. B) twice as many 10-cent coins as there are 20-cents coins? C) twice as many 20-cents coins as there are 10-cents coins

Answer 1

I'd be interested to see these 20 cent coins....  :-)

Lets call them t

Let d = # dimes .. 10 cent coins

 

Total value is $6:

 

.10d + .20t = 6

 

a)  d = t

 

.10d + .20d = 6

.30d = 6

d = 20

20 of each type of coin

 

b)  d = 2t    .... twice as many 10 cent as 20 cent coins

 

.10(2t) + .20t = 6

.20t + .20t = 6

.40t = 6

t = 15 of the 20 cent coins

d = 2t = 20 of the 10 cent coins

 

c)  t = 2d ... twice as many 20 cent as 10 cent coins

 

Try this one the same way as in part b.

.10d + .20(2d) = 6