👤

d varies jointly as r and t. if d =45 when r=15 and t=14, find d when r=21 and t=8?​

Sagot :

Answer:

The value of d when r = 21 and t = 8 is 36.

Step-by-step explanation:

Mathematical Sentence:

[tex]d=rtk[/tex]

Solution for the constant of variation or k:

Given:   [tex]d=45[/tex],   [tex]r=15[/tex],   [tex]t=14[/tex]

Find:   [tex]k=?[/tex]

Formula:   [tex]d=rtk[/tex]

Solution:

[tex]d=rtk\\45=(15)(14)k\\45=210k\\\frac{45}{210}=\frac{210k}{210}\\\frac{45}{210}=k\\k=\frac{3}{14}[/tex]

Final solution for d:

Given:   [tex]r=21[/tex],   [tex]t=8[/tex],   [tex]k=\frac{3}{14}[/tex]

Find:   [tex]d=?[/tex]

Formula:   [tex]d=rtk[/tex]

Solution:

[tex]d=rtk\\d=(21)(8)(\frac{3}{14})\\d=(3)(8)(\frac{3}{2})\\d=(3)(4)(3)\\\boxed{d=36}[/tex]

#CarryOnLearning