1.)
30:bx(b+5)=336
30b/b+150/b = 336
30b+150=336xb
336b-30b=150
306b=150
b=150/306=75/153=25/51 (am simplificat cu2 si apoi cu 3)
a = 30:25/51 =30x51/25=1530/25 =306/5 (am simplificat cu 5)
2.)
a+b = 4 x (a-b)
a+b+a-b=200
2 a =200
a = 200:2, a = 100
a+b = 4x (a-b)
100+b=400-4b
4b+b = 400-100, 5b = 300, b = 300:5 , b=60
3.)pa = pasi adult
pc = pasi copil
2 pa = 3pc
1 pc = 50 cm
2 pa = 150 m
2+3+2+3+....+2+3=2 (1+1+1...1) = 2x20 =40
40x50 = 2000cm= 20 m
de 20 de ori 1 de 20 de ori
