Answer:
16
Step-by-step explanation:
40x 6 =u x 15
240=u x 15
U = 240÷15
U = 16
[tex]40 \div 15 = x \div 6 \\ 40 \div 5 = x \div 2 \\ \\ 5x = 80 \\ x = 16[/tex]