If 3T = 10U and 5U = 7V, then what is the value of T : U : V?

Correct option is B

Given:
3T = 10U
5U = 7V
Solution:
​$$3T = 10U \\T = \frac{10}{3}U \\\\5U = 7V \\U = \frac{7}{5}V \\\\$$​​
Substitute U in terms of V into the equation for T: \\
​$$T = \frac{10}{3} \cdot \frac{7}{5}V \\\ \\ T = \frac{70}{15}V \\\ \\T = \frac{14}{3}V \\\ \\\\$$​​
​$$T : U : V = \frac{14}{3}V : \frac{7}{5}V : V \\$$​​
T : U : V = 70 : 21 : 15

Thus, the ratio T : U : V is 70 : 21 : 15.