Can any kind soul help me

a) 4.50m/s²

b) v= 21

c) 11.25m/s

Step-by-step explanation:

a) rate of change of speed in first 2 seconds

= gradient of graph from t=0s to t=2s

The two points are (0,0) and (2,9).

Rate of change of speed

Total distance= area under graph

Distance travelled for first 6s

= area of traingle +area of rectangle

= ½(2)(9) +(6-2)(9)

= 9 + 4(9)

= 9 +36

= 45m

Distance travelled from t=6s to t=12s

= 135 -45

= 90m

Area under graph from t=6s to t=12s =90

Area of trapezium= 90

½(A +B)(h)= 90

½(9+ v)(6)= 90

3(9 +v)= 90 (simplify)

9 +v= 30 (÷3 throughout)

v= 30 -9

v= 21

c) Average speed

= total distance ÷total time

= 135 ÷12

= 11.25 m/s

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40