a box of 500 Newton covers and area of 20 metre square calculate pressure exerted by the box on the ground

25n/m^-2

Step-by-step explanation:

pressure = Force ÷Area

so, 500 n ÷ 20 m = 25n/m^-2

There were 7 buttons on each card from Elaine's grandmother

In total, there were 40 buttons since there were 5 piles of 8 buttons. Because Elaine had 5 buttons in the pile the other 35 were her grandmother's buttons. If each of the 5 cards had the same number of buttons on them then there would be 7 buttons on each card.