9. Hasan is saving for college. He saves RM1 the first month, RM5 the second month, RM9 the third month and so on. If he starts saving on Jan.1, 2020, how much money will he have saved on June 15, 2021?​

Respuesta :

Answer:

Jun 15, 2021 RM 67

Step-by-step explanation:

2020 Jan 1 (RM)

Feb 5

Mar 9

Apr 13

May 17

Jun 21

Jul 25

Aug 29

Sep 33

Oct 37

Nov 41

Dec 45

2021 Jan 49

Feb 53

Mar 57

Apr 61

May 65

Jun 15, 2021. RM 67

This is an Arithmetic Series for 18 months where a = 1 and d = 4
S(18) = n/2 x (2a + (n -1)d) = 9 x (2x1 + (18 - 1)x4 = 9 x 70 = RM630