Bob has 20 coins totaling $1.30. If he has only dimes and nickels, how many of each coin does he have?

i think it is c, not positive though

step-by-step explanation:

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!

step-by-step explanation:

no solution.