39. A water tank has steps inside it. A monkey is sitting on the topmost step (i.e., the first step). The water level is at the ninth step. (i) He jumps 3 steps down and then jumps back 2 steps up. In how many jumps will he reach the water level? (ii) After drinking water, he wants to go back. For this, he jumps 4 steps up and then jumps back 2 steps down in every move. In how many jumps will he reach back the top step?
Answers
Answer:
1st jump 1+3=4th\ step1+3=4th step
2nd jump 4-2=\ 2nd\ step\4−2= 2nd step
3rd jump 2+3=5th\ step\2+3=5th step
4th jump 5-2=\ 3rd\ step\5−2= 3rd step
5th jump 3+3=6th\ step3+3=6th step
6th jump 6-2=4th\ step6−2=4th step
7th jump 4+3=7th\ step\4+3=7th step
8th jump 7-2\ =\ 5th\ step\7−2 = 5th step
9th jump 5+3=\ 8th\ step\5+3= 8th step
10th jump 8-2=\ 6th\ step\8−2= 6th step
11th jump 6+3=\ 9th\ step\6+3= 9th step
he will reach 9th step in 11th jumps.
(ii) 1st jump = 9-4=\ 5th\ step\9−4= 5th step
2nd jump = 5+2=\ 7th\ step5+2= 7th step
3rd jump = 7-4=\ 3rd\ step\7−4= 3rd step
4th jump = 3+2=\ 5th\ step\3+2= 5th step
5th jump = 5-4=\ 1st\ step\5−4= 1st step
he reach back on the first step in fifth steps.
(iii)
(a) -3+2-3+2-3+2-3+2-3+2-3+2-3+2-3+2=\ -8−3+2−3+2−3+2−3+2−3+2−3+2−3+2−3+2= −8
(b) 4-2+4-2+4-2+4-2=\ 84−2+4−2+4−2+4−2= 8
thus, sum 8 in (b) represents going up by eight steps.
Step-by-step explanation:
1) 3-2 = 1 jumps
He reaches the water level at 1 jumps
2) 5 jumps
3) (a) -3+2-3+2-3+2-3+2-3+2-3=-8
(b) 4 - 2 + 4 - 2 + 4 = 8
8 in (b) represents going up 8 steps.