Question

PICK 2 ANSWERS!!!!!........

Answer 1

the 1st plan has a one time investment of 12000$ and then equal monthly investments of $400

⇒ the 1st plan function can be represented as y = 12000 + 400x

where x is the number of months elapsed

given the 2nd plan function as y = 11000 + 420x

clearly both the functions of 1st plan and 2nd plan are increasing because for each month (that is for consecutive value of x) the value of y increases but does not decrease.

i will explain you by substituting two values for both plans

plan - 1 : function = 12000 + 400x

williams investment after one months is 12000 + 400 = 12400

williams investment in after two months is 12000 + 800 = 12800

we can see that the plan - 1 values are increasing with every month. that is 12400 is increased to 12800. so the function of plan - 1 is increasing.

plan -2 : function = 11000 + 420x

williams investment after one months is 11000 + 420 = 11420

williams investment after two months is 11000 + 840 = 11840

we can see that the plan - 2 values are increasing with every month. that is 11420 is increased to 11840. so the function of plan - 2 is also increasing.

let us caluculate the unit rate of each plan

plan-1 unit rate:

as it is a five year plan. five years contain 60 months

function of plan one = y = 12000 + 400x

at the end of 60 months william paid y = 12000 + 400 × 60 = 36000

unit rate of plan one is 36000/60 = 600$

plan-2 unit rate:

as it is a five year plan. five years contain 60 months

function of plan one = y = 11000 + 420x

at the end of 60 months william paid y = 11000 + 420 × 60 = 36200

unit rate of plan one is 36200/60 = 603$

we can see that unit rate of plan -2 is more as 603 is greater than 600. so the function of plan 2 has a greater unit rate.

if the equation is in the form y = mx + c then c is the y intercept

the equation of 1st plan is y = 12000 + 400x

y intercept of 1st plan = 12000

the equation of 2nd plan is y = 11000 + 420x

y intercept of 2nd plan is 11000

clearly y intercept of 1st plan is greater than the y intercept of 2nd plan because 12000 is greater than 11000