Answer:
answer is 15 coins of 10 cent and 5 coins of 15 cent
let scent coins be x coins be y and so cent
Here
x+y=30 eq1
by letting 5 cent coin be x and 10 cent be 10
10y + 5x = 215 cent (as 2.15$ * 100 =215)
multiplying plying eq 1st by 5 : ( 5x+5y=150)
solving both equation
10y + 5x = 215
-(5y + 5x = 150)
: 5y = 75
y = 15
putting the value of y in eqn 1
x+y: 30
x+15=30
x=15