Question

un elev citeste o carte in:
- prima zi 1 pe 4 din nr de pg
- a doua zi 1 pe 6 din rest
- a treia zi 3 pe 5 din noul rest
- a patra zi are de citit 66 pg
cate pg are cartea?

Answer 1

1zi=1/4*x=x/4
2zi=(x-x/4)*1/6=(4x/4-x/4)*1/6=3x/4*1/6=3x/24=x/8
3zi=(x-x/4-x/8)*3/5=(8x/8-2x/8-x/8)*3/5=5x/8*3/5=15x/40=3x/8
4zi=66 p
x/4+x/8+3x/8+66=x
2x/8+x/8+3x/8+528/8=x
(6x+528)/8=x
6x+528=8x
8x-6x=528
2x=528
x=528:2
x=264