Question 1180013

his selling pattern is an arithmetic sequence



Sn = n/2[(2a+(n-1)d)]

a= 6 , d = 8 Sn = 300

300 - n/2 [ 2*20 + (n-1)*8]

600 = n(40 +8n-8]

600 = 40n^2-32n

/8

75 = 5n^2-4n

5n^2-4n -75=0
 solve for x
x= 4.28 days

On the 5th day he wont meet the demand