\text { Two children are swinging from a } 12 ft \text { long jungle gym that weights } 50 \text { lbs as shown in the figure given } \text { below. The child at } C \text { weights } 70 \text { lbs and the child at } D \text { weights } 60 lbs \text {. Calculate the reactions for the pin } \text { at } A \text { and the roller at B. [In the figure, c.g. refers to center of gravity.] }