Respuesta :
Answer:
s=9
d=6
Step-by-step explanation:
s+d=15
3.s+5.d=57
⇒s=9 và d=6
Answer:
single cone 9, double cone 6
Step-by-step explanation:
Let x be people who took single cone, so 15-x is the ones who took double cone
so,
3x+5(15-x)=57
3x+75-5x=57
2x=18
x=9
single cone = 9
double cone = 15-9 = 6