Question

61+58+55+...+19+16 adalah

Answer 1

Ini merupakan deret aritmatika dengan b= 3
maka,
<=>61+58+55+52+49+46+43+40+37+34+31+28+25+22+19+16=
<=>119+55+52+49+46+43+40+37+34+28+25+22+19+16
<=>174+52+49+46+43+40+37+34+28+22+19+16
<=>226+49+46+43+40+37+34+28+22+19+16
<=>275+46+43+40+37+34+28+22+19+16
<=>321+43+40+37+34+28+22+19+16
<=>364+40+37+34+28+22+19+16
<=>404+37+34+28+22+19+16
<=>441+34+28+22+19+16
<=>475+28+22+19+16
<=>503+22+19+16
<=>525+19+16
<=>544+16
<=>560

Answer 2

S16 = 16/2(2.61+15.(-3))=8(122-45)=616