4) Grandma Lucia brought a basket with 120 cherries to her three grandchildren, Jacopo who is 4 years old, Martino who is 7 years old, and Duccio who is 9 years old. Grandma distributes all the cherries to the grandchildren according to this criterion: she gives each grandchild a number of cherries obtained by multiplying the grandchild's age by a certain factor, and this factor is the same for all three grandchildren. How many cherries are given to Jacopo?
(A) 20,
(B) 21, (C) 22,
(D) 23,
(E) 24.
4. The answer is $\mathbf{( E )}$. Let $a$ be the factor by which each nephew's age must be multiplied to obtain the number of cherries they are entitled to. Then $a(4+7+9)=20 a=120 \mathrm{e}$, so $a$ must be 6. The number of cherries that Jacopo is entitled to is $6 \cdot 4=24$.