Answer:
Step-by-step explanation:
(9*20)-(8*6) = 132 sq cm
Answer:
30mph
Step-by-step explanation:
Kyle rides his bike 30mph,
15mph x 2hrs = 30 mph.
15 miles per hour x 3 is 30mph total.
Hope this helps!
Gauss' method for addition relies on the fact that you can 'pair' certain numbers together. Look at the example:
1+2+3+4+5+6+7+8+9+10
We could manually add all these together from left to right but a clever way to think about this is if we add together the ends of the sum (10+1) we get 11. If we then move one in from the ends and add these (2+9) we also get 11. This means that 1+2+...+9+10 is the same as 11+11+...+11+11.
Because each 2 numbers adds to 11 we know the total number of 11's we have to add together is the length of the sum divided by 2. In our case 5 (10 ÷ 2). We need to add 5 lots of 11 to get our answer. This is the same as 11 × 5 which is easily seen to be 55.
(If you add the 10 numbers together on a calculator you'll see 1+2+3+4+5+6+7+8+9+10 = 55) so this method really makes it a lot quicker.
Looking at your sequence, if we pair the ends together we get 401 (400+1) and we multiply this by the length of the sequence divided by 2. In your case, 200 (400 ÷ 2).
So the sum of all the numbers from 1 to 400 must be 401 × 200 = 80,200.
Remember the steps:
1. Pair the ends together and add them
2. Times this number by the length of the sequence halved
Hope this helps.
(2x + 10)(x - 9)
2x(x - 9) + 10(x - 9)
2x(x) - 2x(9) + 10(x) - 10(9)
2x² - 18x + 10x - 90
2x² - 8x - 90
Good Morning!
Distance = rate x time
1/2 mile = R x 2/5 hour
1/2=2/5R
/2/5 /2/5
R=1/2 x 5/2
R=1 1/4
She can swim 1 1/4 per hour.
I hope this helps! :)
