Answer:
0
Step-by-step explanation:
We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc. For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
Let n be the number 18=60% of n
18=0.6n
18/0.6=n
30=n
Answer:
197 in ^2 (answer B of the list)
Step-by-step explanation:
Notice that this figure has a total of 6 faces, four of which are rectangles (whose area is calculated as "base times height") and two trapezoids (whose area is (B+b)H/2 ).
The total surface area is therefore the addition of these six areas:
Rectangles:
5 in x 5 in = 25 in^2
5 in x 5 in = 25 in^2
5 in x 6.4 in = 32 in^2
9 in x 5 in = 45 in^2
Trapezoids:
Two of equal dimensions: B = 9 in, b = 5 in, H = 5 in
2 * (9 in + 5 in) 5 in /2 = 70 in^2
Which gives a total of (25 + 25 + 32+45 + 70) in^2 = 197 in^2
This agrees with answer B of he provided list.
Answer:
Weight of Train A = 454 tons
Weight of Train B = 35 tons
Step-by-step explanation:
It is given that:
Let,
A represent weight of Train A
B represent weight of Train B
According to given information:
A + B = 489 Eqn 1
A - B = 419 Eqn 2
Adding Eqn 1 and 2
A + B + A - B = 489 + 419
2A = 908
Dividing both sides by 2
Putting A = 454 in Eqn 1
454 + B = 489
B = 489 - 454
B = 35
Therefore,
Weight of Train A = 454 tons
Weight of Train B = 35 tons
