Flag 9 grade maths> If 3x – y = 5 and 4x – 3y = 1, find p, if...
question mark

  1. If 3x – y = 5 and 4x – 3y = 1, find p, if y = px – 3.
  2. A man covers 150 km in 5 hours by boating down the current and returns in 7 and ½ gours against the current. Determine the speed of the boat and the current.

Adwaita Bhattacharyya , 10 Years ago
Grade 9
anser 1 Answers
SHAIK AASIF AHAMED

Last Activity: 10 Years ago

Hello student,
Please find the answer to your question below
1)Given 3x-y=5.......(1)
4x-3y=1......(2)
Multiplying equation 1 by 3 we get 9x-3y=15....(3)
4x-3y=1......(4)
Subtracting 4 from 3 we get 5x=14
so x=14/5
substituting x=14/5 in 4x-3y=1 we get y=17/5
So x=(14/5) and y=(17/5)
Also given y=px-3
So (17/5)+3=p(14/5)
so p=16/7
2)let speed of boat=b,speed of current=c
So given b+c=150/5=30km/hr
b-c=150/7.5=20km/hr
SO b+c=30...(1)
b-c=20.....(2)
Adding 1 and 2 we get 2b=50 so b=25
Substituting b=25 in 1 we get c=5
So Speed of boat(b)=25km/hr
Speed of current(c)=5km/hr

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