Answer:
D
Step-by-step explanation:
A. Sin 42=0.669
Cos=52=0.617
B. Sin 90=1
cos 90=0
C. cos30=0.866
sin 70=0.940
D. sin80=0.985
cos 10=0.985
Check the picture below.
so, bearing in mind that vertical angles are equal, thus ∡AED = ∡BEC, and we know that ∡BEC = 52 = ∡AED, so those two angles added up are 104°.
now, a circle has a total of 360°, if we take away those 104° from the red angles, what's leftover is just 256°, well, the green angles there are also vertical angles and thus twins, so each one will take half of 256°.
∡BEA = 128° = ∡CED.
Answer:
13800
Step-by-step explanation:
The order of the members is important (because each selected member will receive a different position), thus we then need to use the definition of permutation.
There are 25 members, of which 3 are selected.

Evaluate the definition of a combination:

Answer:
10/10
Step-by-step explanation:
Answer:
The merchant buys 30 shirts originally.
Step-by-step explanation:
Let us assume that the merchant bought x numbers of shirts in $120.
So, the cost for each shirt is $
.
Now, if the cost for each shirt is reduced by 1$, then he would have bought 10 shirts more i.e. (x + 10) shirts in $120.
So, we can write the following equation as
⇒(120 - x)(x + 10) = 120x
⇒ 120x - 10x + 1200 - x² = 120x
⇒ x² +10x - 1200 = 0
⇒ x² + 40x - 30x - 1200 = 0
⇒(x + 40)(x - 30) = 0
⇒ x = - 40 or x = 30
But x can not be negative.
Hence, the merchant buys 30 shirts originally. (Answer)