Question

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ᴍᴀᴛʜꜱ
ᴄʟᴀꜱꜱ 10
ᴄʜ - qᴜᴀᴅʀᴀᴛɪᴄ ᴇqᴜᴀᴛɪᴏɴꜱ
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ɪ.ᴇ.qᴜᴇꜱᴛɪᴏɴ ɴᴏ.6

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Answer 1

Let x be the usual speed of the plane

Increased speed=x+250

Time taken by plane in usual circumstaces,t

1

=

speed

distance

t

1

=

x

1500

Time taken by plane due to delay, t

2

=

x+250

distance

Difference in times = Delay in departure

x

1500

−

x+250

1500

=

60

30

x

1500

−

x+250

1500

=

2

1

⇒

x

2

+250x

x+250−x

=

3000

1

x

2

+250x−750000=0

Solving:

x

2

+1000x−750x−750000=0

x(x+1000)−750(x+1000)=0

(x−750)(x+1000)=0

x=750

∴ The usual speed of the plane is750 km/h.

Answer 2

Hello Dear!

Here is your answer.

kindly refer to the attachment!