To replace the trees destroyed by typhoon Yolanda, the forestry department of Tagaytay has developed a ten-year plan. During the first year they will plant 100 trees. Each succeeding year, they will plant 50 more trees than they planted the year before.

a. 1,000 trees

b. 3,250 trees

Step-by-step explanation:

a. How many trees will they plant during the fifth year?

b. How many trees will they have planted by the end of the tenth year?

Using the sum of an arithmetic progression formula

Sn = n/2 {2a+(n-1)d}

Where,

Sn = Sum of an n terms

n = number of terms

a = first term

d = common difference

a.

n = 5

a = 100

d = 50

S5 = n/2 {2a+(n-1)d}

= 5/2 {2*100 + (5-1)50}

= 5/2 {200+(4)50}

= 5/2{200 + 200}

= 5/2(400)

= 2,000 / 2

= 1,000

S5 = 1,000 trees

b. Sn = n/2 {2a+(n-1)d}

n = 10

a = 100

d =50

S10 = 10/2{2*100 + (10-1)50}

= 5{200 + (9)50}

= 5{200 + 450}

= 5(650)

= 3,250

S10 = 3,250 trees

answer: i oofed

step-by-step explanation:

oofed=wow