Aboy has twice as many nickels as dimes and 5 more half dollars than nickels. if the total value of the coins is $6.10, how many of each coin has he?

He has 6 nickels, 3 dimes and 11 half dollars

Step-by-step explanation:

Let x = Number of dimes then by the statements in the question we have

that the number of nickel is 2x and the number of half dollars is 5 + 2x (remember the number of nickels is twice number of dimes). Then we can set up an equation which will show the total value of $ 6.10 $ the boy has ;

x dimes have a value of 0.10 x

2x nickels have a value of 0.10 x

5+ 2x half dollar have a value of 0.50*(5 + 2x) or 2.50 + x

adding all together we have

010x + 0.10x + 2.50 + x  = 6.10

solving for x  gives us a value of  3.60/1.20  which equal 3 there follows the answer 3 dimes, 6 nickels and 11 half dollars

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.