The below diagram shows the system of the two masses.
The gravitational field intensity due to the mass A is calculated as, EA‌‌=‌
GMA
r2CA
‌‌=G‌
90
(32)
‌‌=10G
∧
r
CA The gravitational field intensity due to the mass B is calculated as EB‌‌=‌
GMB
r2CB
‌‌=G‌
160
(42)
=10G
∧
r
CB The resultant of EA and EB is E‌‌=√EA2+EB2 ‌‌=√(10G)2+(10G)2 ‌‌=10√2G Substitute the value of the G E‌‌=10√2G ‌‌=10√2×6.67×10−11 ‌‌=9.43×10−10Nkg−1