Dinosaurs

More than 30 and less than 60 dinosaurs have met at the pond. A quarter of them bathed and 1/7 saws and the rest gripped. How many were at the pond? How many were there?

Result

n =  56
j =  8

Solution:

$n_{1}=4 \cdot \ 7=28 \ \\ 30 < n < 60 \ \\ n=2 \cdot \ n_{1}=2 \cdot \ 28=56$

$j=n/7=56/7=8$

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