jack and betty have 28 coins that are nickles and dimes. if the vaule of the coins is $1.95 . how many nickles do they have

Question

They have 28 coins in total Nickles and Dimes.

Answer 1

let n number of nickels and d number of dimes

we have n+d=28 (1)  and  0.05n+0.1d=1.95 (2) (one nickel = 0.05 of one dollar, and one dime =0.1 of one dollar) . from the (1) we get n=28-d  plugging this value to (2) we get 0.05(28-d)+0.1d=1.95

multiplying both sides by 100 we get  5(28-d)+10d=195 --->>. 140-5d+10d=195. --->>> 5d=55 so d=11

from (1) we get n=28-11 = 17

so Jack and Betty have 17 nickels (and 11 dimes)