Question

The given table shows a relationship between x and y.


If the rate is kept constant for all the floors, the number of plants at ground level is .

• A. 6
• B. 4
• C. 7
• D. 9

Answer 1

The correct option is C 7


From table consider any two points, say (6,25) and (15,52).

$\text{Slope (m)}=\frac{\text{Change in y}}{\text{Change in x}}=\frac{52-25}{15-6}=3$

$\text{Equation for point slope form is}$
$y-y_1=m(x-x_1)$

At point (6,25), we get:
$y-25=3(x-6)$

$\Rightarrow y-25=3x-18$
(using distributive property)

$\Rightarrow y=3x+7$

To find the number of plants at the ground level, we have to put x = 0 in the eqaution.

By putting x = 0, we get:

$y=3x+7$
$\Rightarrow y=3\left(0\right)+7$
$\Rightarrow y=7$

So, the value of y-intercept = 7

∴ The number of flowering plants at ground level is 7.