Question

Numarul "a" reprezinta 40% din "b"
a) Demonstrati ca numerele a si b sunt direct proportionale cu 2 si 5
b)Calculati a si b daca 3a-b=10

Answer 1

A=40/100×b=4/10×b=2/5×b
3a-b=10
6/5×b-b=10
6b-5b=50
B=50
A=2/5×50=100/5=20

Answer 2

a=40%b=2b/5
b=100%=1
a/b=40/100=2/5 deci a si b direct proportionale cu 2 si 5


b)3a-b=10
a=2k
b=5k
3×2k-5k=10
6k-5k=10
k=10
a=2×10=20
b=5×10=50