2 diamond rings and 4 silver rings cost $1300. A diamond ring and a silver ring cost $510. How much is a diamond ring?

370

Step-by-step explanation:

510 times 2 is 1020 - cost for 2 diamond and 2 silver

1300-1020 is 280 - cost for remaining 2 silver

280 divided by 2 = 140 - cost for each silver

510-140 is cost for 1 dimond = 370

$370

Step-by-step explanation:

(D-Diamond rings S-Silver Rings)

2D + 4S = $1300

D + S = $510

2D+4(510-D)=1300

2D+2040-4D=1300

2040-2D=1300

-2D=1300-2040

-2D=-740

D=370

510-370=140

S=140

Diamond Ring - $370

Silver Ring - $140

d (5 x (-20)) * (100 x (0.7))

step-by-step explanation:

5÷1/100 * -.7 *-20

copy dot flip

5*100 * -.7 *-20

rearrange

5*-20   * 100 *-.7

-100   *-70

7000