10)Notam : porumbel-p si gaina-g
p+g=50
p=3g/2
3g/2+g=50
3g/2+2g/2=50
5g/2=50
5g=50*2=>5g=100
g=100/5=20 ( ani gaina )
20+p=50
p=50-20=30( ani porumbel )
12)3 * 35/7 = 3* 5= 15 ( ani oaie )
13)trei numere consecutive adica : a, b=a+1, c=a+2 .
a+2cm=1m+20cm
a+2cm=100cm+20cm
a+2cm=120cm
a=118cm
b=a+1=118cm+1=119cm
c=a+2=118cm+2=120cm