y varies jointly as x and z. If y = 5 when x = 3 and z= 4, find y when x = 6 and z = 8.
Mathematics
lilleeashlyn
Question
y varies jointly as x and z. If y = 5 when x = 3 and z= 4, find y when x = 6 and z = 8.
1 Answer

1. User Answers jimrgrant1
Answer:
y = 20
Stepbystep explanation:
Given y varies jointly as x and z then the equation relating them is
y = kxz ← k is the constant of variation
To find k use the condition y = 5 when x = 3 and z = 4
5 = k × 3 × 4 = 12k ( divide both sides by 12 )
[tex]\frac{5}{12}[/tex] = k
y = [tex]\frac{5}{12}[/tex] xz ← equation of variation
When x = 6 and z = 8 , then
y = [tex]\frac{5}{12}[/tex] × 6 × 8 = [tex]\frac{5}{12}[/tex] × 48 = 5 × 4 = 20