Question

According to a plan, a drilling team had to drill to a depth of 270 metres below the ground level. For the first three days the team drilled as per the plan. However, subsequently finding that their resources were getting underutilised according to the plan, it started to drill 8 metres more than the plan every day. Therefore, a day before the planned date they had drilled to a depth of 280 metres. The drilling plan for each day was

Answer 1

Thank you for asking this question. The options for this question are missing. here are the missing options:

A)38 meters  

B)30 meters

C)27 meters

D)None of these

Answer:

We know that each drilling metre = x

days to be drilled= y

xy = 270

3x + (x+8) (y-4) = 280

8y-x=42

Now we will substitute y=270/x

x²+ 42x - 2160 =0

x = 30

If there is any confusion please leave a comment below.

Answer 2

Answer:

Step-by-step explanation:

each drilling metre = x

days to be drilled= y

so,xy=270 {given}

now,

3x+(x+8)(y-4)= 280 { 3x why? bz for 3 days drilling is according to the old plan ,no changes, so days multiplied by drilling meter ;

(x+8) why? bz its given in question now every day the drillling meter increases by 8 metre;

(y-4) why? bz total days in starting we have taken y, 3 days got used drilling metre as it is,plus one before work got completed,so it becomes y- 3-1=y-4;

(x+8)(y-4) got multiplied i.e meter *no.of days}

8y-x=42 { by using above two equations}

now,substitute y=270/x from 1st equation

x^2+42x-2160=0

x=30;

or u can direct substitute value of y in terms of x n get the same ans