Inverse Variation If I varies inversely with R and I = 0.15 when R = 50, which equation should be used to show this relationship? A.I=7.5/R B.I=7.5R C.IR=0.75 D.I=R/7.5 If x varies inversely with y and x = 8 when y = 6, find y when x =10. A. y=40/3 B.y=5/12 C. y = 7.5 D. y = 4.8 xy = –12. What is the constant of variation for this relationship? A. –1.2 B. -1/4 C. –0.12 D. –12 V varies inversely with T and V = 18 when T = 3. Which equation shows this relationship? A.V=6/T B.V=6T C.V=54/T D.V=54T the 4 is in the doc.
Answer (2)
( 1 ) R ⋅ I = a an d 50 ⋅ 0.15 = a ⇒ a = 7.5 ⇒ I = R 7.5 ⇒ A n s . A . ( 2 ) x ⋅ y = a an d 8 ⋅ 6 = a ⇒ a = 48 ⇒ x y = 48 ⇒ 10 y = 48 ⇒ y = 4.8 ⇒ A n s . D . ( 3 ) x y = − 12 ⇒ co n s t an t = − 12 ⇒ A n s . D .
( 4 ) x y = − 12 e . g . : x = 3 an d y = − 4 or x = − 3 an d y = 4 ⇒ A n s . A . ( 5 ) V ⋅ T = a an d 18 ⋅ 3 = a ⇒ a = 54 ⇒ V ⋅ T = 54 ⇒ V = T 54 ⇒ A n s . C .
The answers are: 1) A: I = 7.5/R; 2) D: y = 4.8; 3) D: -12; 4) C: V = 54/T.
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