D because that is the mean
Answer:
a. 90
b. 360
Step-by-step explanation:
The time taken by humming bird to flap its wings= 0.08 sec
by flying 7.2 seconds a typical giant hummingbird flap its wings 
times
= 90 times
Since, A ruby-throated hummingbird can flap its wings 4 times faster than a giant hummingbird, it will flap its wings in every 0.02 sec
so in 7.2 seconds it will flap 
times = 360 times
6 × 2 = 12 so 6 is the dilation factor
thus 4 × 6 is PQ which is 24
Answer:
750 grams of 60% alloy
Step-by-step explanation:
Define x = amount of 60% alloy and y = amount of 20% alloy
Equating the amounts of gold:
0.6x+0.2y = 1000(0.5)
Since there must be 1000 grams total:
x+y = 1000
Writing the 2 resulting equations together:
0.6x + 0.2y = 500
x + y = 1000
Multiply the first equation by 5:
3x + y = 2500
x + y = 1000
Subtracting the 2nd equation from the 1st:
2x = 1500
x = 750
Answer: 750 grams of 60% alloy
Answer:
A&D
Step-by-step explanation:
i think
