Question

un calator a parcurs in prina zi 30℅ din drum, in a doua zi 2/5 din restul drumului, iar in ultima zi 42 km. aflati lungimea drumului.

Answer 1

X - drumul total

1) 30/100 • x = 3/10 • x

2) 2/5 • (x - 3/10 • x) = 2/5 • ( x - 3x/10 ) = 2/5 • 7x / 10 = 7x / 25

3) 42 km

3/10 • x + 7x/25 + 42 = x
3x / 10 + 7x / 25 + 42 = x
15 x +14 x + 2100 = 50 x
29 x + 2100 = 50 x
21 x = 2100
X = 100

Raspuns : 100 km