Turysta przeszedł 72 km w ciągu 3 dni. Pierwszego dnia przeszedł najwięcej, drugiego dnia - dwa razy mniej niż pierwszego, a trzeciego dnia połowę tego co pierwszego i drugiego dnia w sumie. Ile kiometrów turysta przeszedł każdego dnia?

Za odp. Daje naj. P. S książka : Matematyka z Kluczem 7 zad 3/240

On the first day, he went 32 km, the second day he traveled 16 km, and the third day he traveled 24 km.

Let x be the amount traveled the first day. The second day he went "twice less," or half as much, so 1/2x. the third day, he went 1/2 of the previous two days' total:

1/2 (x+1/2x) = 1/2 (3/2x) = 3/4x.

Adding these three together, we have:

x+1/2x+3/4x = 72

Find a common denominator. 4 is the first thing 2 and 4 will both divide evenly into:

4/4x + 2/4x + 3/4x = 72

9/4x = 72

Divide both sides by 9/4:

9/4x : 9/4 = 72 : 9/4

x = 72/1 : 9/4

x = 72/1 * 4/9

x = 288/9

x = 32

The first day was 32; half of that makes the second day 16; the total of those two is 48, and half of that is 24.