We can use ratios and the cross-multiply-divide to find this.
The ratio 21:5 is avaliable via the question. We then need to compare that to the ratio x:100, the 100 being the percent and the x being the number of airplane parts.
21/5 = x/100
We can then solve for x to find the number of airplane parts. First we multiply by 100 on both sides to get 2100/5 = x. Therefore x = 420 and there are 420 airplane parts.
Answer:
a = 9
Step-by-step explanation:
you can simplify the proportion to:

use cross- multiplication
8a = 72
a = 9
Answer:
just multiply 7 by 21 and 21 by 7
like
2*21/7*21. + 10*7/21*7
41/147+ 70/147
111/147. Ans
Answer:
=
+
+
Step-by-step explanation:
=multiple ways to climb a tower
When n = 1,
tower= 1 cm
= 1
When n = 2,
tower =2 cm
= 2
When n = 3,
tower = 3 cm
it can be build if we use three 1 cm blocks
= 3
When n = 4,
tower= 4 cm
it can be build if we use four 1 cm blocks
= 6
When n > 5
tower height > 4 cm
so we can use 1 cm, 2 cm and 4 cm blocks
so in that case if our last move is 1 cm block then
will be
n —1 cm
if our last move is 2 cm block then
will be
n —2 cm
if our last move is 4 cm block then
will be
n —4 cm
=
+
+
Answer:
It is D
Step-by-step explanation:
6 x 11 = 66
3 x 9 = 27