How do I make an equation for this? I always have trouble with these
Jose has a total of 28 dimes and quarters altogether. The total value of the coins is $4.15. How many quarters does Jose have?
Let x be the number of dimes and let y be the number of quarters:
Then $\displaystyle x + y = 28$ ................................(1)
since he has the amount in dollars, try to write x and y in terms of dollars:
so,
$\displaystyle \frac{x}{10} + \frac{y}{4} = 4.15$....................(2)
(2) can be simplified as:
$\displaystyle \frac{4x+10y}{40} = 4.15 \Longrightarrow 4x+10y = 166$....................(3)
Note that the denominators in the above equation(2) denotes the number of coins that make a dollar. 10 dimes = $1 and 4 quarters = $1
Now can you solve equations (1) and (3) for the values of x and y???
you will have
19 dimes
9 quarters