Suppose the ratio of Lev's age to Mina's age is 1 : 2 and the ratio of Mina's age to Naomi's age is 3 : 4.
If the sum of all three ages is between 10 and 20, then how old is Mina?
+150 Lev's age = L
Mina's age = M
Naomi's age = N
\(\frac{L}{M}=\frac{1}{2}=\frac{3}{6}\) => \(\frac{M}{N}=\frac{3}{4}=\frac{6}{8}\)
L = 3a
M = 6a
N = 8a
a = 1
M = 6
