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# The distance(D km) that sally cycles varies directly as her speed (S km/h). So D=kS. She cycles 16km at an average speed of 8km/h.

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The distance(D km) that sally cycles varies directly as her speed (S km/h). So D=kS. She cycles 16km at an average speed of 8km/h.

a) Find a formula connecting D and S.

Ans= D= 2S (I think this is correct)

b) How far would she cycle at 9km/h?

I need help with this one.

Oh and there's another question I need help with:

The number of dollars (D) is directly proportional to the number of pounds (P) exchanged. Three dollars can be exchanged for 2 pounds.

a) Find a formula for D.

Ans= D=1.5P

b) How many dollars can be obtained with 12 pounds?

I need help with this question.

Jun 29, 2015

#1
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1st b)  Assuming k stays the same (i.e. at 2 hours), then D = 2*9 or D = 18 km

2nd b)  Again assuming the proportionality constant stays the same, then D = 1.5*12 or D = \$18

Jun 29, 2015

#1
+27475
+5

1st b)  Assuming k stays the same (i.e. at 2 hours), then D = 2*9 or D = 18 km

2nd b)  Again assuming the proportionality constant stays the same, then D = 1.5*12 or D = \$18

Alan Jun 29, 2015