Answer:
315 chairs
Step-by-step explanation:
This question can instill your quick calculation skills which can be very useful when it comes to event planning.
1 row of chairs = 15 chairs
21 rows of chairs = 15 x 21
= 315 chairs.
Answer:
Δ MNO ≅ ΔXYZ by AAS postulate.
Step-by-step explanation:
Given:
,
, and YO = NZ.
Consider YO = NZ
Add OZ on both sides
YO + OZ = NZ + OZ
YZ = NO
Consider triangles Δ MNO and ΔXYZ.
Statement Reason
1.
Given
2.
Given
3. YZ = NO ∵ YO = NZ
Therefore, the two triangles Δ MNO and ΔXYZ are congruent to each other from AAS postulate as two corresponding angles and a corresponding side are equal to each other.
The appropriate method to use in solving the given question is permutation. Then, the numbers of ways to arrange the buttons is 1320 ways.
In the given question, the order of arrangement is important, so that the number of ways that Fiona could order the buttons can be determined by permutation method.
i.e 
= 
Red 6
Green 3
Yellow 3
Total 12
Since no two neighbouring buttons of the same colour is allowed, then 3 buttons would be arranged at a time.
Thus, n = 12 and r = 3;

= 
= 
= 
= 12 x 11 x 10

= 1320
Therefore the buttons can be arranged in 1320 ways without two neighbors having the same colour.
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Answer:
Step-by-step explanation:
2 * L + 2 * W = 68
2*L = 2* 9x = 9x + 9x
2*W = 2*8x = 8x + 8x
Since the perimeter is 68
9x + 9x + 8x + 8x = 68
5(3)-3(-2)
15-(-6)=
15+6=21
a negative plus a negative is a positive so its 21
4(3)-3(-2)
12-(-6)
12+6=18
21+18=39